source string | id string | question string | options list | answer string | reasoning string |
|---|---|---|---|---|---|
SciQ | SciQ-544 | biochemistry, kinetics
A select few, however, bind more strongly, and are not released by the structure changes of the receptor. When this happens, the receptor is stuck in the "on" position. One of two things then happens; either the receptor continues to activate, causing neural impulses which your brain eventually ignores (odor fatigue), or mechanisms inside the cell notice the faulty receptor, bring it into the cell in a process similar to endocytosis, and attempt to break down its components and fix the damage to reuse it. More often than not, the bound chemical ends up poisoning the cell by binding to something more vital than an ordinary G-protein receptor, eventually triggering programmed cell death. That's fine; the basal cells behind the surface of the olfactory epithelium divide fast enough to replenish every cell in the nasal membrane about once every two days.
Sources: Wikipedia - Olfactory epithelium, Olfactory receptor and G protein-coupled receptor.
The following is multiple choice question (with options) to answer.
When the number of active receptors falls below that threshold, what happens to the cellular response? | [
"it ceases",
"it stabilizes",
"it responds",
"it increases"
] | A | |
SciQ | SciQ-545 | neuroscience, neurophysiology, neurotransmitter
Title: Correlation between morphology of neurons and neurotransmitters Are there known significant (positive or negative) statistical correlations between the morphology type of neurons and the neurotransmitters that they use (presynaptic, i.e. transmitters that are released, and postsynaptic, i.e. transmitters that are received)?
This question assumes, that a definite set of morphology types has been defined. The answer depends on this definition, of course. Yes, at least for the neurotransmitters that a given cell releases.
As far as the neurotransmitters a cell responds to, you are really better off thinking in terms of receptor expression. Most neurons will express receptors for many different neurotransmitters. It's far too broad to go into them all in an answer here.
As far as the transmitters that cells release, morphological types of neurons are very often associated with release of particular neurotransmitters. In the cortex, for example, pyramidal cells principally release glutamate while there are potentially dozens of morphological types (again, depending on how you define them) that release GABA; in the cerebellum, Purkinje neurons release GABA whereas granule cells release glutamate.
However, be careful: some terms like "granule cell" don't really refer to a special morphological type. They are really just describing "small cells in close proximity": these can be completely different types in different brain regions. It really makes no sense to ask these types of questions for the brain as a whole, you have to study individual brain regions, each of which is organized quite differently from the others.
The following is multiple choice question (with options) to answer.
Types of neurons include sensory neurons, motor neurons, and? | [
"histones",
"synapses",
"anions",
"interneurons"
] | D | Types of neurons include sensory neurons, motor neurons, and interneurons. |
SciQ | SciQ-546 | human-biology, immunology
Title: Are there any viruses or bacteria which have evolved to withstand higher temperatures due to fever My question was raised after receiving this information:
The primary reason the body raises its temperature (via the Hypothalamus in this case) is that bacteria and viruses tend to optimally thrive at 98.6F, which is also your body's optimal operating temperature.
I am just wondering if there are any viruses or bacteria that have gained the ability to prosper under fever temperatures through evolution? If not, why not? Is there any biological restriction stopping such viral evolution?
Update:
I will try to explain my question. As far as I know, evolution helps species to adapt to their environment. For example, when people started using antibiotics we got new bacteria resistant to those antibiotics.
If fever is part of the innate immune reaction to viruses and bacteria, why hasn't this resulted in selection for fever-resistant variants? Why has evolution apparently stopped in this case? Fever is just one of the many ways of the body's defense mechanism work. Under infection, human body can raise body temperature, release cytokins and activate white blood cells etc. Sometimes the bacteria can evade immune suppression or immune complement fixation so that they can stay inside a "fever-ish" body like they just don't care. Example: Pseudomonas aeruginosa. They can grow in 42 degree Celsius which surpass the normal fever temperature.
My answer may not be the best for your question. All I'm trying to say is that fever acts as a supportive role during an infection. Human body relies on heavy artilleries such as white blood cells and cytokin to clear the infection. That's why it will be more beneficial for the bacteria to evolve abilities to evade immune suppression and immune complement fixation. And bacteria know how to do those.
The following is multiple choice question (with options) to answer.
Active and passive forms of what enable the body to resist damage from pathogens? | [
"immunity",
"autonomy",
"stem cells",
"potential"
] | A | Active versus Passive Immunity Immunity to pathogens, and the ability to control pathogen growth so that damage to the tissues of the body is limited, can be acquired by (1) the active development of an immune response in the infected individual or (2) the passive transfer of immune components from an immune individual to a nonimmune one. Both active and passive immunity have examples in the natural world and as part of medicine. Active immunity is the resistance to pathogens acquired during an adaptive immune response within an individual (Table 21.6). Naturally acquired active immunity, the response to a pathogen, is the focus of this chapter. Artificially acquired active immunity involves the use of vaccines. A vaccine is a killed or weakened pathogen or its components that, when administered to a healthy individual, leads to the development of immunological memory (a weakened primary immune response) without causing much in the way of symptoms. Thus, with the use of vaccines, one can avoid the damage from disease that results from the first exposure to the pathogen, yet reap the benefits of protection from immunological memory. The advent of vaccines was one of the major medical advances of the twentieth century and led to the eradication of smallpox and the control of many infectious diseases, including polio, measles, and whooping cough. |
SciQ | SciQ-547 | newtonian-mechanics, classical-mechanics, angular-velocity, rotational-kinematics
$$
The rotational energy of the system is the sum of rotational energies of the particles:
$$
E_\text{rot} = \sum_i \frac{\;\; L_i^2}{2J_i}
$$
There are two translational energies:
The following is multiple choice question (with options) to answer.
What is the energy of motion called? | [
"kinetic energy",
"potential energy",
"binary energy",
"mixed energy"
] | A | |
SciQ | SciQ-548 | mycology
Does this mean that not only is going to the swimming pool not a cure of fungal infections, but it is actually the cause? Well, maybe not. While the articles show that there is a larger incidence of fungal infections among swimmers, they only show correlation, not causality. People who partake in sports activities have a bigger chance of having these infections than the general public. These are also the people who are more likely to go swimming.
To settle the matter for good, we need an article named "Prevalence of fungal infections among occasionally swimming couch potatoes" :-)
The following is multiple choice question (with options) to answer.
What is the term for an infection caused by a fungal parasite? | [
"mydriasis",
"mitosis",
"acrobasis",
"mycosis"
] | D | |
SciQ | SciQ-549 | sleep, hearing, perception
Title: What is the term for awareness of or inclusion of real sounds within a dream? I fell asleep while listening to a podcast, and I am sure I was dreaming but I could also still hear the podcast.
The podcast played an important role in the dream, I was searching for the source of the voice, wondering if others in the dream could hear the same voice. I started to feel a bit panicky and woke up as the podcast also happened to end. I rewound the show and confirmed that it was all there, exactly as I had heard in my dream!
I would like to read more about this type of experience, but I am having trouble finding the right words to search. Is there a name for this phenomenon? Is there anything that contributes to experiences like these? I know it wasn't lucid dreaming, because I wasn't aware of being asleep. I think I found a good expression : "sensory incorporation in dreams"
https://www.psychologytoday.com/blog/dream-factory/201409/sensory-incorporation-in-dreams
It doesn't seem reflected in a Google Scholar search however, and I don't find a consistent terminology in the papers that do seem to be about the subject. That article can be a good starting point though.
EDIT: other good one: "influence of external stimuli on dreams".
https://journals.ub.uni-heidelberg.de/index.php/IJoDR/article/view/15754
The following is multiple choice question (with options) to answer.
What do you call the ability to sense sound energy and perceive sound? | [
"sensory deprivation",
"tuning",
"echolocation",
"hearing"
] | D | Hearing is the ability to sense sound energy and perceive sound. The ear is the organ that senses sound and allows us to hear. Damage to structures of the ear may cause hearing loss. Total hearing loss is called deafness. |
SciQ | SciQ-550 | physiology, botany, measurement
Title: Possible calculations with temperature, humidity, images and VIS spectrum of a plant in an Integrating sphere I am currently working on a project which involves growing some plants in a integrating sphere made of foam. I have added temperature, humidity and soil moisture sensors as well as a Spectrometer (350 - 800nm) and a webcam which takes images of the plant every 30 minutes.
I thought of calculating the LAI (Leaf area index) from the webcam images.
Does anyone have any other suggestions/ideas on what I could calculate with the given data from these sensors? With the images you could, perhaps, assess growth rate of the plant which can be plotted against spectral content of light to investigate effects of light quality on growth. Using moist and water and temperature the same can be done. Multivariate analysis can help to implement all the values, while ANCOVA may may help to correct for covariance.
A detailed experimental set up may help to answer this question. Not specifically the hardware, but how the effect of water stress is measured. E.g., are multiple plants tested under different watering conditions? In that case all the other measures (temperature, light) are probably used to check whether everything is constant across all specimens except water availability. This may limit the usefulness of analysis of these additional measures. I think the other parameters (light, water, temperature) may be not so interesting other than covariates for water stress as they are either not controlled or deliberately kept constant. Moreover, probably their effects on plants are pretty obvious too.
The following is multiple choice question (with options) to answer.
Some plants can detect increased levels of what when reflected from leaves of encroaching neighbors? | [
"light",
"oxygen",
"air",
"water"
] | A | |
SciQ | SciQ-551 | waves, oscillators, string
Is the principal the same as for the transverse waves? There is a few reasons why I can't really see that working: the rotational waves in this case are sometimes so large that the flat part goes vertical (i.e. against the wind) or even rotates by multiple revolutions.
The most important one: Why is the wavelength of the rotation waves (i.e. the separation of the nodes as can be seen in the picture) so much lower than for the transverse waves? This is an observation that is not obvious from the picture, but usually there are only like 3 or 4 oscillations nodes for the transverse ones and like 30 for the rotational ones.
The question will get too broad if I ask more questions about this, so let's focus on the above. I am generally interested in this phenomenon and there are other questions I can't quite answer (e.g. when it is not very windy there aren't any oscillations and sometimes when the wind is weak oscillations come and go. So why is there a "critical wind speed" at which they start resonating up?). I'm having a problem visualizing the transverse waves with 3 or 4 nodes you mention. All videos I've found show standing waves with only two nodes, the slackline moving up and down between the anchor points (or between an anchor point and the person walking the slackline).
The rotation waves I saw (maybe torsion oscillation is a better name) also had only two nodes. The "nodes" in the picture aren't actual nodes, they are points where the twist angle corresponds to the viewing angle. If the middle of the line makes (a bit more than) seven complete rotations, you'll have 14 positions on the left and on the right where the rotation is a multiple of 180 degrees, giving you 28 visual points. Their number indicates the amplitude of the torsional oscillation rather than the number of nodes.
The following is multiple choice question (with options) to answer.
What are the high points of a transverse wave called? | [
"troughs",
"peaks",
"crests",
"ridges"
] | C | A transverse wave can be characterized by the high and low points reached by particles of the medium as the wave passes through. This is illustrated in Figure below . The high points are called crests, and the low points are called troughs. |
SciQ | SciQ-552 | thermodynamics, solid-state-physics, electric-current, conductors, metals
Title: Why is the heat flow in metals slower than the current flow? When we apply a voltage across a metallic conductor, the current starts to flow almost instantaneously. But when a temperature difference is established across the same conductor, the flow of heat is much slower. It takes larger time for the heat to reach from one end to the other than the current. Why is this so? The current flows almost instantaneously because it is driven by an electric field which appears across the conductor almost instantaneously (near the speed of light). All electrons in the conductor are set into motion by a chain reaction. Collectively they all move through the conductor at what is called the drift velocity at the same time.
By contrast, heat transfer by conduction requires the transfer of energy by collisions between particles in the material that starts at the high temperature end of the conductor and progresses gradually to the low temperature end of the conductor. In the case of metals, the particles are primarily electrons.
Hope this helps.
The following is multiple choice question (with options) to answer.
What is the transfer of heat by a current? | [
"radiation",
"diffusion",
"convection",
"combustion"
] | C | Convection is the transfer of heat by a current. Convection happens in a liquid or a gas. Air near the ground is warmed by heat radiating from Earth's surface. The warm air is less dense, so it rises. As it rises, it cools. The cool air is dense, so it sinks to the surface. This creates a convection current, like the one in Figure below . Convection is the most important way that heat travels in the atmosphere. |
SciQ | SciQ-553 | evolution, cell-biology
What do you mean by multicellularity?
The evolution of multicellularity can be discussed in the context where sister cells form an organism together or when unrelated cells (among the same species or even cells from different species) come together to form an organism. Also, the multicellularity can be discussed at a different level depending on how we want to define multicellularity. Is a stack of cells reproducing individually, working for their own benefit a multicellular? Do we need a division of labor? Do we need a division between germline (reproductive caste) and soma line (non-reproductive case)?
How many times did multicellularity evolve independently?
Some people consider that there are multicellular bacteria (biofilms) but we will avoid discussions that are based on limit-case definitions. Let's talk about eukaryotes. Most Eukaryotes are unicellular and multicellularity evolved many times independently in eukaryotes. To my knowledge, complex multicellularity however evolved only (only?) 6 times independently in eukaryotes.
The following is multiple choice question (with options) to answer.
When acellular slime molds swarm, they fuse together to form a single cell with many what? | [
"digestive tracts",
"lungs",
"cytoplasm",
"nuclei"
] | D | When acellular slime molds swarm, they fuse together to form a single cell with many nuclei. |
SciQ | SciQ-554 | energy, electrostatics, potential-energy
Title: where is electrostatic potential energy stored?
Potential energy can be defined as the capacity for doing work which arises from position or configuration.In the electrical case, a charge will exert a force on any other charge and potential energy arises from any collection of charges.
Where is this potential energy stored and how? That actually gets a bit tricky at the advanced level, but at the basic level, you should find somewhere in your textbook the equation $U = \int d^3x \left(\frac{1}{2} |\vec{E}|^2 \right)$ (maybe with a different constant up front, depending on what system of units the book is using). So at any point in space, the electric field $\vec{E}(\vec{x})$ at that point "stores" an amount of potential energy $\frac{1}{2} |\vec{E}|^2$.
The following is multiple choice question (with options) to answer.
Potential energy is not only associated with the location of matter, but also with the structure of matter. even a spring on the ground has potential energy if it is what? | [
"ignored",
"watched",
"coupled",
"compressed"
] | D | Potential energy is not only associated with the location of matter, but also with the structure of matter. Even a spring on the ground has potential energy if it is compressed; so does a rubber band that is pulled taut. On a molecular level, the bonds that hold the atoms of molecules together exist in a particular structure that has potential energy. Remember that anabolic cellular pathways require energy to synthesize complex molecules from simpler ones and catabolic pathways release energy when complex molecules are broken down. The fact that energy can be released by the breakdown of certain chemical bonds implies that those bonds have potential energy. In fact, there is potential energy stored within the bonds of all the food molecules we eat, which is eventually harnessed for use. This is because these bonds can release energy when broken. The type of potential energy that exists within chemical bonds, and is released when those bonds are broken, is called chemical energy. Chemical energy is responsible for providing living cells with energy from food. The release of energy occurs when the molecular bonds within food molecules are broken. |
SciQ | SciQ-555 | composite-resin
Title: Stop cardboard from warping when impregnating with polyester resin I have a guitar and also the rectangular cardboard box which it was delivered in. I want to make a more durable carry case for the guitar using the cardboard delivery box. It seems a shame to throw away a perfectly good box which is already the correct size and I don't want to buy a guitar case just yet. Dimensions of the box are 100x45x17 centimeters. The cardboard is made from two layers of corrugated material sandwiched in three layers of flat. I find from research that the cardboard needs to be sealed first with pva/wood glue after which fine woven glass cloth and then polyester resin can be applied. In previous experiments (when I didn't understand the necessity to seal it first) the cardboard warped and destroyed the shape of my project which was a tea tray. My question is how can I stop the cardboard from warping? If successful with the glassfibre I then want to apply a final color coat( I think this is called a gel coat). Consider that the typical multi-layer corrugated cardboard material has all the flutes running parallel/in the same direction. In order to minimize the warping you are experiencing, it would be necessary to create additional layers by using adhesive to bond "cross-grain" cardboard to the existing surface. You'd have to pick an adhesive, perhaps via experimentation that would not create warping while being applied or while curing.
PVA/wood glue is water based and will indeed warp while creating the new layers. Contact cement is not water based (unless you buy that particular product!) and will provide strong bonds between layers.
Additionally, gel coat is usually applied as the first layer within a mold, excluding ambient atmosphere during the curing process. Be sure to select a gel coat product which provides for this aspect of your build. For outer skin application, the terms "gel coat with wax" will provide suitable results in a search. Useful information at the linked site.
The following is multiple choice question (with options) to answer.
What is the name of film that polyester fibers form? | [
"mylar",
"fabric",
"layers",
"Softness"
] | A | Polyester molecules make excellent fibers and are used in many fabrics. A knitted polyester tube, which is biologically inert, can be used in surgery to repair or replace diseased sections of blood vessels. PET is used to make bottles for soda pop and other beverages. It is also formed into films called Mylar. When magnetically coated, Mylar tape is used in audio- and videocassettes. Synthetic arteries can be made from PET, polytetrafluoroethylene, and other polymers. |
SciQ | SciQ-556 | genetics, molecular-biology, mutations
Title: Are introns conserved among cells? To elaborate on the title: Among somatic, post-mitotic cells, would the same intron on a given chromosome have the same sequence among all cells descended from a progenitor cell? I believe that the kind of mutation that you are interested in is somatic mutation, as opposed to germ-line mutation.
Any given genomic locus (intron, exon, intergenic region) probably doesn't mutate most of the time. In the case of somatic mutation, it is yet more likely that no mutation happens.
Nonetheless, such mutations do happen, in all of those different regions. For example, here is a study that catalogs somatic mutations in introns that lead to a particular phenomenon called intronic polyadenylation; here is another that catalogs intronic mutations that mess up splicing.
The same is true for protein-coding somatic mutations, one can find similar catalogs of mutations for those.
Such mutations in different regions (intronic, exonic, and otherwise) are all of interest as events that can lead to cancer.
None of this should distract us from that fact that usually mutations don't happen at any given site. But it's a question of probabilities, not of absolutes.
The following is multiple choice question (with options) to answer.
Where do germline mutations occur in? | [
"in spores",
"in gametes",
"in aggregations",
"In blood cells"
] | B | Germline mutations occur in gametes. Somatic mutations occur in other body cells. Chromosomal alterations are mutations that change chromosome structure. Point mutations change a single nucleotide. Frameshift mutations are additions or deletions of nucleotides that cause a shift in the reading frame. |
SciQ | SciQ-557 | everyday-chemistry, safety
80% hydrochloric acid
That does not exist in water. Water won't take up that much hydrogen chloride gas under normal conditions. Concentrated hydrochlorid acid (~ 38%) should be fine.
80% nitric acid
That's close to fuming nitric acid and again a pretty strong oxidant. I'd say that you're safe, but don't take my word for it ;)
The following is multiple choice question (with options) to answer.
What a mixture of nitric acid and hydrochloric acid? | [
"aqua regia",
"crystal regia",
"sulfate regia",
"acidus regia"
] | A | Aqua regia, a mixture of nitric acid and hydrochloric acid, is one of the few materials that will dissolve gold. This material, translated to "royal water" in English, was named so because it could dissolve the royal metal gold. First noted in the fourteenth century, aqua regia could be used to help ascertain whether a particular material was actually gold or was some trickery of the alchemist. Nitric acid by itself will not dissolve gold, but will in combination with hydrochloric acid. The chemistry of the process is rather complex, with both acids reacting with the metal to form soluble gold compounds. The gold can be recovered from the solution, making the process useful for purification purposes. |
SciQ | SciQ-558 | species-identification, mycology
Title: What is these mushrooms in my indoor pot? I am living in Japan and in summer, it's very hot and humid even inside my room.
Today, I've found two mushrooms in the pot of a plant.
What is this species? It's very surprising than within one day they grew like this. They do look a lot like a common mushroom called "shaggy mane" mushroom (Coprinus comatus). This may not be a correct identification though, so do not eat them. They are widespread around the world, but usually grow outside.
Yes it is amazing how rapidly the fruiting body of many fungi can grow. I am providing an interesting Wikipedia link with more information. You can also search to find other images using Google images online.
https://en.wikipedia.org/wiki/Coprinus_comatus
The following is multiple choice question (with options) to answer.
Most members of what kingdom of spore-making organisms grow on the forest floor, where the dark and damp environment is rich? | [
"algae",
"moss",
"fungi",
"bacteria"
] | C | Habitats Although fungi are primarily associated with humid and cool environments that provide a supply of organic matter, they colonize a surprising diversity of habitats, from seawater to human skin and mucous membranes. Chytrids are found primarily in aquatic environments. Other fungi, such as Coccidioides immitis, which causes pneumonia when its spores are inhaled, thrive in the dry and sandy soil of the southwestern United States. Fungi that parasitize coral reefs live in the ocean. However, most members of the Kingdom Fungi grow on the forest floor, where the dark and damp environment is rich. |
SciQ | SciQ-559 | thermodynamics
Title: Why aerosol forms when you take a hot shower in a very cold day? When temperature is about $\pu{17 ^\circ C}$ and I open the hot shower in maximum temperature (for a common electric shower) the air gets almost immediately full of droplets and this lasts the entire bath.
I guess there is water vapor in the air and it gets cooled fast and condenses. If this is true, I don't get where the vapor comes from. As air temperature increases(in the vicinity of the hot shower) air can hold more water molecules, or with more technical terms: the saturation water pressure increases with the temperature.
Near the water, the air temperature is high and since there's plenty of hot water that evaporates then the vapor pressure increases. Then because of convective motion, new cold air replaces the hot one and it becomes full of water vapor as well. The previously warm air is now far away from the hot water and it is starting to cool down. When its temperature decreases it can't hold so many water molecules and therefore you observe the small droplets of condensed water.
Ref. picture https://www.chemguide.co.uk/physical/phaseeqia/vapourpress.html
The following is multiple choice question (with options) to answer.
What results when the water vapor from a hot shower contacts the cooler surface of a mirror? | [
"foggy mirror",
"cleaner mirror",
"the mirror breaks",
"mirror brightens"
] | A | If you take a hot shower in a closed bathroom, the mirror is likely to "fog" up. The "fog" consists of tiny droplets of water that form on the cool surface of the mirror. Why does this happen? Some of the hot water from the shower evaporates, so the air in the bathroom contains a lot of water vapor. When the water vapor contacts cooler surfaces, such as the mirror, it cools and loses energy. The cooler water particles no longer have enough energy to overcome the forces of attraction between them. They come together and form droplets of liquid water. |
SciQ | SciQ-560 | genetics, botany, twins
In a number of varieties, two and sometimes three megaspores were functional, giving rise to several embryo sacs. On fertilization, embryos develop in these, causing the phenomenon of pseudopolyembryony.
Therefore this source seems to agree with the first.
However, a more recent paper Martínez-Gómez, P., & Gradziel, T. M. (2003). Sexual polyembryony in almond. Sexual plant reproduction, 16(3), 135-139., focused on almonds, suggests that certain almond cultivars are prone to true polyembryony, though it seems like the additional seeds are often a bit stunted and have high mortality. They also reference a paper purporting to mention polyembryony in peach, Toyama, T. K. (1974). Haploidy in peach. HortScience, 9, 187-188., though I cannot find this article in anything but Japanese - the title, however, suggests that these may be haploid polyembryos, which also occur with the almonds - these are indeed from division of the same embryo, but because they are haploid they would not actually be genetically identical, since each is taking half of the diploid chromosomes.
With only these limited descriptions to go by, which seem to be mostly observational rather than backed by any systematic study, I would hesitantly conclude that most likely what you are seeing is a fruit in which two separate ovules developed together, and therefore could be as genetically different as any two different peaches from the same tree. True polyembryos seem to be possible in stone fruits, but as a mostly rare occurrence that is only common in particular strains - when it does occur, it may be via haploidy, which means the seeds will still be genetically distinct.
The following is multiple choice question (with options) to answer.
What type of vascular plants produce seeds in cones? | [
"gymnosperms",
"angiosperms",
"lipids",
"Proteins"
] | A | Gymnosperms are vascular plants that produce seeds in cones . Examples include conifers such as pine and spruce trees. The gymnosperm life cycle has a dominant sporophyte generation. Both gametophytes and the next generation’s new sporophytes develop on the sporophyte parent plant. Figure below is a diagram of a gymnosperm life cycle. |
SciQ | SciQ-561 | gene, networks, sequence-homology
Title: Are gene names same across species? I have a bunch of gene names of Apis mellifera (specifically 194). I used these gene names as an input on STRING database to create a network for Drosophila melanogaster. 54 of those genes were also present in D. melanogaster and I received a second network. Is this a credible method of creating homologous gene network. Or should I use the sequences of the 194 genes and BLAST it to the geneset of the D. melanogaster and do it that way? You could try using BioMart in Ensembl Metazoa. Filter by your list of gene names in honeybee, then get the fly homologues as attributes. The homologues are calculated by sequence comparison and clustering.
The following is multiple choice question (with options) to answer.
In fruit flies, all homeotic genes are found on one what? | [
"genome",
"chromosome",
"site",
"enzymes"
] | B | |
SciQ | SciQ-562 | immunology, sleep, immunosuppression
Title: Is the immune system suppressed during sleep? Of course we have heard that during stress our immune system is suppressed. This leads me to wonder, does the immune system get suppressed when we are sleeping and why? During both these conditions the body might need to save energy for other biochemical processes, so I wouldn't be surprised that the immune system is suppressed while a person is asleep. During stress glucocorticoids, which are steroid hormones produced by adrenal glands (such as cortisol and corticosterone), are released into the blood-stream. These hormones have anti-inflammatory effects. You may say that they suppress the immune system.
The circadian rhythm, which controls the sleep-wake cycle, also controls glucocorticoid secretion, thereby reinforcing the sleep-wake responses [1]. Sleep deprivation is a form of stress and it causes an elevation in the levels of glucocorticoids. The effect of sleep deprivation could be replicated by adrenectomy (surgical removal of adrenal glands); there is a transcriptional downregulation of several neuroprotective genes [2]. Via glucocorticoid mediated signalling, sleep deprivation also results in inhibition of adult neurogenesis in the hippocampus [3].
Another study says that cytokine (TNFα and IL6) secretion by immune-system cells, are inherently affected by circadian rhythm via a glucocorticoid independent mechanism [4].
Overall, sleep is inversely correlated with reduced inflammation because both the processes are under the control of the circadian clock. Sleep deprivation, as a form of stress, is also correlated with glucocorticoid secretion. It should be understood that sleep doesn't necessarily inhibit glucocorticoid secretion and it would be incorrect to say that reduced inflammatory effects are because of sleep.
The following is multiple choice question (with options) to answer.
Certain medications can suppress the immune system. this is an intended effect of drugs given to people with what? | [
"benign tumors",
"infections",
"genetic disorders",
"transplanted organs"
] | D | Certain medications can suppress the immune system. This is an intended effect of drugs given to people with transplanted organs. In many cases, however, it is an unwanted side effect of drugs used to treat other diseases. |
SciQ | SciQ-563 | inorganic-chemistry, bond
Title: Backbonding in molecules like BF3 Can anyone please briefly explain to me the concept of backbonding along with necessary conditions for backbonding with some example? As I understand, backbonding is a donation of electron from electron-rich to vacant orbital, but I don't know anything else.
$\ce{BF3}$ has trigonal plannar structure all the three $\ce{B-F}$ bonds lie in plane and thus p-orbitals of boron and fluorine become parallel.
Boron has empty p-orbital and p-orbital of fluorine contains lone pair, and hence boron acts as Lewis acid and fluorine as Lewis base. Fluorine donates its lone pair to boron and this bonding is called backbonding.
The following is multiple choice question (with options) to answer.
The geometry of the bf 3 molecule is called what? | [
"fractal planar",
"spherical planar",
"trigonal planar",
"distorted planar"
] | C | The geometry of the BF 3 molecule is called trigonal planar . The fluorine atoms are positioned at the vertices of an equilateral triangle. The F-B-F angle is 120°, and all four atoms lie in the same plane. |
SciQ | SciQ-564 | evolution, cell-biology
What do you mean by multicellularity?
The evolution of multicellularity can be discussed in the context where sister cells form an organism together or when unrelated cells (among the same species or even cells from different species) come together to form an organism. Also, the multicellularity can be discussed at a different level depending on how we want to define multicellularity. Is a stack of cells reproducing individually, working for their own benefit a multicellular? Do we need a division of labor? Do we need a division between germline (reproductive caste) and soma line (non-reproductive case)?
How many times did multicellularity evolve independently?
Some people consider that there are multicellular bacteria (biofilms) but we will avoid discussions that are based on limit-case definitions. Let's talk about eukaryotes. Most Eukaryotes are unicellular and multicellularity evolved many times independently in eukaryotes. To my knowledge, complex multicellularity however evolved only (only?) 6 times independently in eukaryotes.
The following is multiple choice question (with options) to answer.
In multicellular organisms, mutations can be subdivided into germline mutations and? | [
"resultant mutations",
"comparative mutations",
"elective mutations",
"somatic mutations"
] | D | Once again, a mutation is the change in the DNA or RNA sequence. In multicellular organisms, mutations can be subdivided into germline mutations and somatic mutations. Germline mutations occur in the DNA of sex cells, or gametes, and are therefore potentially very serious. These mutations can be passed to the next generation. If the zygote contains the mutation, every cell in the resulting organism will have that mutation. If the mutation results in a disease phenotype, the mutation causes what is called a hereditary disease. Somatic mutations , which occur in somatic, or body, cells, cannot be passed to the next generation (offspring). Mutations present in a somatic cell of an organism will be present (by DNA replication and mitosis) in all descendants of that cell. If the mutation is present in a gene that is not used in that cell type, the mutation may have no effect. On the other hand, the mutation may lead to a serious medical condition such as cancer. |
SciQ | SciQ-565 | species-identification, mycology, mushroom
Title: Species ID: Buckyball-like fungus Previous research
A friend of mine shared a link of some beautiful fungi: https://i.stack.imgur.com/B81Pu.jpg. I was intrigued by the curious critter below -- it seems to have honed the power of buckyball geometry, presumably much before we Humans ever did (search: Buckminsterfullerene to learn about a feat of chemical engineering).
Google reverse-image search almost got me the answer I needed, but no species name.
I've asked friends on Facebook with no answers yet.
Question
What is the name of this species of fungus?
Related Questions on Stack Biology
Here's a related Species Identification question of a fungus: Puffball mushroom species ID? (by @rg255)
EDIT: I'm an idiot... the Imgur had species names, thus answering my question, post-mortem. Thanks @skymningen for pointing that out. Looks very similar to Clathrus ruber fungus.
Be careful, it is poisonous.
The following is multiple choice question (with options) to answer.
What is the name for a biologist who studies fungi? | [
"egyptologists",
"mycologists",
"musicologists",
"oncologists"
] | B | Mycologist Mycologists are biologists who study fungi. Mycology is a branch of microbiology, and many mycologists start their careers with a degree in microbiology. To become a mycologist, a bachelor's degree in a biological science (preferably majoring in microbiology) and a master's degree in mycology are minimally necessary. Mycologists can specialize in taxonomy and fungal genomics, molecular and cellular biology, plant pathology, biotechnology, or biochemistry. Some medical microbiologists concentrate on the study of infectious diseases caused by fungi (mycoses). Mycologists collaborate with zoologists and plant pathologists to identify and control difficult fungal infections, such as the devastating chestnut blight, the mysterious decline in frog populations in many areas of the world, or the deadly epidemic called white nose syndrome, which is decimating bats in the Eastern United States. Government agencies hire mycologists as research scientists and technicians to monitor the health of crops, national parks, and national forests. Mycologists are also employed in the private sector by companies that develop chemical and biological control products or new agricultural products, and by companies that provide disease control services. Because of the key role played by fungi in the fermentation of alcohol and the preparation of many important foods, scientists with a good understanding of fungal physiology routinely work in the food technology industry. Oenology, the science of wine making, relies not only on the knowledge of grape varietals and soil composition, but also on a solid understanding of the characteristics of the wild yeasts that thrive in different wine-making regions. It is possible to purchase yeast strains isolated from specific grape-growing regions. The great French chemist and microbiologist, Louis Pasteur, made many of his essential discoveries working on the humble brewer’s yeast, thus discovering the process of fermentation. |
SciQ | SciQ-566 | mechanical-engineering, thermodynamics, heat-transfer, chemistry, heat
Title: In case of solvation , Who converts gaseous ions to aqueous ? Why do we even have gaseous but not solid ions? We take Nacl and dissolve it in water. There is formation of $Na^+$ and $Cl^-$ gaseous ions along with 2H+ and $Cl^{2-}$ aqueous ions.
Then , Na+ is attracted towards $Cl^{2-}$ and 2H+ is attracted towards $Cl^-$ ions.
Energy required by water molecules to separate the NaCl molecules is knows as Lattice enthalpy.
Energy required to form aqueous NaCl molecule is called hydration enthalpy.
My questions are:
Who is the one that converts gaseous ions of NaCl to aqueous ions?
During the dissolution of NaCl, why is there no formation of solid ions first but directly, it states that gaseous ions of NaCl are formed?
Also We define reactions uniquely depending on the reactants and products. Here are examples related to your question.
Formation: Na(s) + (1/2)Cl$_2$(g) $\rightarrow$ NaCl(s)
Lattice Formation: Na$^+$(g) + Cl$^-$(g) $\rightarrow$ NaCl(s)
Solution: NaCl(s) $\rightarrow$ NaCl(aq)
Hydration: Na$^+$(g) $\rightarrow$ Na$^+$(aq)
Atomization: Na(s) $\rightarrow$ Na(g)
A significant observation here is that the STATE of the reactants and products is also required because it is a unique identifier.
As to your questions ...
Who is the one that converts ...
We can convert NaCl(s) to gaseous ions experimentally through processes that may involve multiple steps, including vaporization and ionization.
During the dissolution of NaCl(s), why is there no formation of solid ions first but directly, it states that gaseous ions of NaCl are formed?
The following is multiple choice question (with options) to answer.
How many different kinds of ions are produced when sodium chloride dissociates ? | [
"one",
"five",
"two",
"three"
] | C | The sodium chloride dissociates into two ions, while the glucose does not dissociate. Therefore, equal concentrations of each solution will result in twice as many dissolved particles in the case of the sodium chloride. The vapor pressure of the sodium chloride solution will be lowered twice the amount as the glucose solution. |
SciQ | SciQ-567 | inorganic-chemistry
Title: Why is the ratio between Silicon and Oxygen 1:3 in single chain silicates? I thought that the ratio of silicon to oxygen in a silica tetrahedron was 1:4, so if a single chain is just many of these linked together, why does the ratio become 1:3? Silicon has 2 complete oxygen atoms ($2\times1=2$) and 2 equally shared oxygen atoms ($2\times1/2=1$), total 3.
The following is multiple choice question (with options) to answer.
What mineral is made of one silicon atom and two oxygen atoms? | [
"pumice",
"quartz",
"cobalt",
"glass"
] | B | 5. Quartz is made of one silicon atom and two oxygen atoms. If you find a mineral and find that it is made of one silicon atom and one oxygen atom is it quartz?. |
SciQ | SciQ-568 | cell-biology, meiosis, mitosis
Title: Is the cell cycle applicable to meiosis as well, or just mitosis? All the diagrams I can find, show the cell cycle as having G1 phase (growth 1), S phase (DNA replication), G2 (growth 2) before the Mitotic phase (mitosis + cytokinesis).
Is there an equivalent "cell cycle" for meiosis, since the chromosomes in parent cell in meiosis also having "double" the genetic material prior to cell division (presumably from DNA replication too)?
Is it simply the same cell cycle as mitosis but with a Meiotic phase instead of Mitotic?
If so, would appreciate if anyone had a diagram :) Thanks! The cell cycle is only associated with mitosis. The cell cycle is the normal process of cell division with which cells can indefinitely increase their number by cyclically repeating the process. When a cell goes through the cycle, the result is two cells that are genetically identical.
Meiosis is a special type of cell division (which can occur only in eukaryotes) that produces cells that are not genetically identical to the initiating cell. The number of chromosomes in each of the resulting cells is half the number that were in the initial cell. (These haploid cells can later participate in fertilization, producing a cell with the original number of chromosomes.) Many of the steps of meiosis are similar to the steps involved in mitosis, but overall the process is more complex. Since meiosis reduces the number of chromosomes, it cannot be repeated and so does not take part in a cell division cycle.
The following is multiple choice question (with options) to answer.
How many cycles do cells have? | [
"seven",
"four",
"two",
"six"
] | B | This diagram represents the cell cycle in eukaryotes. The cell cycle depicts the life of an eukaryotic cell. The cell cycle has four phases: the first growth or gap (G 1 ) phase, the synthesis (S) phase, the second growth or gap (G 2 ) phase and the mitotic (M) phase. The M phase includes mitosis and cytokinesis. The cell spends the majority of the cycle in the first three phases (G 1 , S, G 2 ) of the cycle, collectively known as interphase. After cytokinesis, two genetically identical daughter cells are formed. |
SciQ | SciQ-569 | thermodynamics, statistical-mechanics
Title: Why do particles of an ideal gas move in random motion? Suppose we imagine that the particles (no molecules) of a helium gas are all initially moving horizontally at the same speed.(there is no interaction among them, and the container is ideal, in the sense that the particles scatter horizontally when they hit it) Would at least some later be moving vertically?
If they were completely organized in the beginning, would they get sprayed around at all angles, and then would the sprayed ones get sprayed some more, and sprayed some more, and sprayed some more?
What would be the origin of the random motion of the particles of a helium gas , for example, in a perfect box? Uncertainty principle? You could design initial conditions for a gas for which it doesn't move in brownian motion, just like you described. It's just that that takes some really particular initial conditons, and life is way too messy for that to happen frequently. Not only that, considering that there are on the order of $~10^{23}$ particles in a macroscopic object, the word "infrequently" here becomes "so rare that it has most likely never happened anywhere in the visible universe".
For example, start with your suggestion, and imagine you trap the particles in a box. They will hit a wall, ricochet off at different angles, collide into each other, and soon you will once again have a mess of particles moving unpredictable directions. This kind of thing is very typical and that's why any gas you see in real life will have random motion with probability which is unfathomably close to 100%.
The following is multiple choice question (with options) to answer.
Gas particles can move randomly in what directions? | [
"some directions",
"all directions",
"few directions",
"one direction"
] | B | Christopher Auyeung. Gas particles move randomly in all directions . CC BY-NC 3.0. |
SciQ | SciQ-570 | atoms, terminology
Title: What is a neutral atom? I was told that an atom's atomic number is defined as follows:
The number of electrons or protons present in a neutral atom is called atomic number. It is represented by Z.
What does neutral mean here? Why isn't it just "..present in an atom..."? Electrons and protons are charged particles. The electrons have negative charge, while protons have positive charge. A neutral atom is an atom where the charges of the electrons and the protons balance. Luckily, one electron has the same charge (with opposite sign) as a proton.
Example: Carbon has 6 protons. The neutral Carbon atom has 6 electrons. The atomic number is 6 since there are 6 protons.
The following is multiple choice question (with options) to answer.
The total number of protons and neutorns in an atom is called what? | [
"atom number",
"volume number",
"mass number",
"formation number"
] | C | The mass number is defined as the total number of protons and neutrons in an atom. |
SciQ | SciQ-571 | standard-model
Title: What if the stationary mass of fundamental particular were different? My question is the following:
Consider the possibility of existing variations of the elementary particles whose stationary mass were 100 times smaller. I mean, electrons and other fundamental particles with 1/100 (or 1/1000) the stationary mass they have. All other things remaining equal, my questions are:
Such particles would be able to form atoms?
Said atoms could form molecules and macroscopic bodies?
Which different properties would we expect that such bodies could have? They obviously would be much lighter, but would they interact with light differently? Would we be able to see them? Would we be able to touch and feel them?
Such particles would enable the existence of stable elements with higher atomic numbers, like stable versions of low half-life elements? I suppose by stationary mass you mean what is usually called
rest mass or invariant mass.
So let us assume the rest masses of all elementary particles
(electrons, quarks, ...) are $100$
times smaller than they are in our universe.
Such particles would be able to form atoms?
Yes, because the electromagnetic interaction between charges
is still there. But according to quantum mechanics
the atoms would be $100$ times larger.
Said atoms could form molecules and macroscopic bodies?
Yes, but the molecules and macroscopic bodies
would also be $100$ times larger, because they are
governed by the electromagnetic interaction as well.
Which different properties would we expect that such bodies
could have? They obviously would be much lighter, but would
they interact with light differently? Would we be able to see
them? Would we be able to touch and feel them?
The atomic and molecular binding energies
would be $100$ times smaller.
Therefore the energy of photons emitted/absorbed by
atoms and molecules would also be $100$ times smaller.
And hence the light frequencies would be $100$ times smaller
and the light wavelengths would be $100$ times larger.
So the world experienced by us would be essentially the
same, just scaled differently.
Such particles would enable the existence of stable elements
with higher atomic numbers, like stable versions of low half-life elements?
The following is multiple choice question (with options) to answer.
All matter is composed of tiny indivisible particles called atoms. all atoms of an element are identical in mass and this? | [
"chemical properties",
"acid properties",
"liquid properties",
"electrical properties"
] | A | All matter is composed of tiny indivisible particles called atoms. All atoms of an element are identical in mass and chemical properties, whereas atoms of different elements differ in mass and fundamental chemical properties. A chemical compound is a substance that always contains the same atoms in the same ratio. In chemical reactions, atoms from one or more compounds or elements redistribute or rearrange in relation to other atoms to form one or more new compounds. Atoms themselves do not undergo a change of identity in chemical reactions. This last hypothesis suggested that the alchemists’ goal of transmuting other elements to gold was impossible, at least through chemical reactions. We now know that Dalton’s atomic theory is essentially correct, with four minor modifications:. |
SciQ | SciQ-572 | lightning
lightning is essentially just an huge electric arc from the clouds to the ground, correct?
Wrong, the current actually may start from the ground. That is the rational of the lightning rods, to create a path for a current to be generated by the potential difference to the cloud and to meet the current from the clouds in a prefered location instead of a random one. It is not wise to stand next to a rod, read in the link the amount of power dissipated by a bolt.
The average peak power output of a single lightning stroke is about one trillion watts — one "terawatt" ($10^{12}$ W ), and the stroke lasts for about 30 millionths of a second — 30 "microseconds".[18]
And it is not wise to stand, because you may also give rise to leaders that will meet the lightning path. If in the open it is best you fall on the ground as much sheltered as possible.
A colleague once was about 20 meters from a lightning bolt, and he was so shocked by the sound and fury, it took him a week to come down to normal.
The following is multiple choice question (with options) to answer.
Where do lightnings build up? | [
"clouds",
"stratosphere",
"air",
"troposphere"
] | A | Lightning is the discharge of static electricity that has built up on clouds. Every year, the earth experiences an average of 25 million lightning strikes. Lightning bolts travel at speeds up to 60,000 miles per second, and can reach temperatures of 50,000°F, which is five times the temperature of the surface of the sun. The energy contained in a single lightning strike could light a 100 Watt light bulb 24 hours per day for 90 days. |
SciQ | SciQ-573 | It would seem that you're making the mistake of assuming the pattern is linear. When you're finding all configurations of non-0 digits in the case in which m is 1, there should be just as many configurations of 0 digits in the case in which m is 9. So: $$xxxxxxxxx0,0xxxxxxxxx$$
If your linear calculation were accurate, then there should be 10000000000 ways to place that singular 0 digit! Hope that helps!
The following is multiple choice question (with options) to answer.
What do we call zeros that appear after nonzero digits? | [
"left-end zeros",
"significant digits",
"right-end zeros",
"placeholders"
] | C | 4. Zeros that appear after all nonzero digits are called right-end zeros. Right-end zeros in a number that lacks a decimal point are not significant. A. 140 has two significant figures. |
SciQ | SciQ-574 | bond, orbitals
Title: What are overlap integrals? I came across something called overlap integrals. I could understand that it is something about the overlapping of orbitals. What is it actually? Reduce the problem to one dimension first. The overlap integral between two functions, $f = f(x)$ and $g = g(x)$, is defined by
$$S_{fg} = \int_{-\infty}^\infty [f(x)]^*g(x)\,\mathrm{d}x$$
where $^*$ denotes complex conjugation. $S$ is the common symbol for the overlap integral; the subscript $fg$ indicates that it is the overlap between $f$ and $g$.
So, for example, let's try a simple case: let
$$f(x) = g(x) = \left(\frac{m\omega}{\pi \hbar}\right)^{1/4} \exp\left(-\frac{m\omega x^2}{2\hbar}\right)$$
(the ground state of the quantum harmonic oscillator). This function is real, so the complex conjugation doesn't do anything. We have
$$\begin{align}
S_{fg} &= \int_{-\infty}^\infty \left(\frac{m\omega}{\pi \hbar}\right)^{1/2} \exp\left(-\frac{m\omega x^2}{\hbar}\right)\,\mathrm{d}x \\
&= \sqrt{\frac{m\omega}{\pi\hbar}} \int_{-\infty}^\infty \exp\left(-\frac{m\omega x^2}{\hbar}\right)\,\mathrm{d}x \\
&= \sqrt{\frac{m\omega}{\pi\hbar}} \sqrt{\frac{\pi\hbar}{m\omega}} \\
&= 1
The following is multiple choice question (with options) to answer.
What term is used to describe a bond formed by the overlap of orbitals in an end-to-end fashion, with the electron density concentrated between the nuclei of the bonding atoms? | [
"rna bond",
"sigma bond",
"lattice bond",
"beta bond"
] | B | It is necessary to distinguish between the two types of covalent bonds in a C 2 H 4 molecule. A sigma bond (σ bond) is a bond formed by the overlap of orbitals in an end-to-end fashion, with the electron density concentrated between the nuclei of the bonding atoms. A pi bond (π bond) is a bond formed by the overlap of orbitals in a side-by-side fashion, with the electron density concentrated above and below the plane of the nuclei of the bonding atoms. Figure below shows the two types of bonding in C 2 H 4 . The sp 2 hybrid orbitals are orange and the p z orbital is green. Three sigma bonds are formed by each carbon atom with its hybrid orbitals. The pi bond is the “second” bond of the double bond between the carbon atoms and is shown as an elongated blue lobe that extends both above and below the plane of the molecule, which contains the six atoms and all of the sigma bonds. |
SciQ | SciQ-575 | electromagnetism, thermodynamics, energy, work, radiation
Title: Is energy only transmitted through electromagnetic and particle radiations? Which are the other ways of transmission if any? If energy does not require any medium for transmission(as for sunlight reaching earth, the heat too), is it transmitted in quanta in particle radiation too? Energy transfer can be thought to occur via the exchange of a 'virtual particle'. In nature, there are 4 fundamental forces, namely:
1. Electromagnetic force
2. Gravitational force
3. Strong force
4. Weak force
Each of these forces have a different exchange particle:
For instance, the exchange particle for EM is a photon whereas that for the strong force is the gluon. The nature of the interaction is characterised by the properties of the exchange particle.
Now if you want to connect this rather abstract idea to a bigger picture of the more 'real world', you just have to carefully think about what the process you are considering actually involved on a deeper level.
For example: suppose you are pushing a box across your room. What you are actually doing is repelling the electrons on the box by the electrons on your hands, thus causing it to move. Therefore, you the interaction is an electromagnetic interaction and hence the exchange particles involved are photons.
If you think of energy transfer in this way, then indeed all energy transfers occur via 'particle exchanges' or radiation (since you a particle is essentially a wave packet [wave particle duality]).
The following is multiple choice question (with options) to answer.
According to count rumford, which two are equivalent ways of transferring energy? | [
"addition and multiplication",
"heat and work",
"osmosis and heredity",
"time and space"
] | B | In the 1780s, an American scientist named Benjamin Thompson, also known as Count Rumford, was hired by the Elector of Bavaria to supervise the manufacture of cannons. During the manufacturing process, teams of horses harnessed to a large-toothed wheel supplied the power needed to drill a hole several inches in diameter straight down the center of a solid brass or bronze cylinder, which was cooled by water. Based on his observations, Rumford became convinced that heat and work are equivalent ways of transferring energy. |
SciQ | SciQ-576 | signal-detection, software-defined-radio, frequency-modulation
¹ Bessel functions, by the way. You don't want to analytically deal with those.
² $\frac{(108 - 87)\,\text{MHz}}{50\,\text{kHz}}=\frac{21\cdot10^3}{5\cdot10^1}=420$
The following is multiple choice question (with options) to answer.
What type of radio waves exist in the 540 to 1600 khz frequency range? | [
"am radio waves",
"fm radio waves",
"microwaves",
"sound waves"
] | A | AM radio waves are used to carry commercial radio signals in the frequency range from 540 to 1600 kHz. The abbreviation AM stands for amplitude modulation, which is the method for placing information on these waves. (See Figure 24.12. ) A carrier wave having the basic frequency of the radio station, say 1530 kHz, is varied or modulated in amplitude by an audio signal. The resulting wave has a constant frequency, but a varying amplitude. A radio receiver tuned to have the same resonant frequency as the carrier wave can pick up the signal, while rejecting the many other frequencies impinging on its antenna. The receiver’s circuitry is designed to respond to variations in amplitude of the carrier wave to replicate the original audio signal. That audio signal is amplified to drive a speaker or perhaps to be recorded. |
SciQ | SciQ-577 | immunology, lab-techniques, flow-cytometry, cell-sorting
Without lysis, the RBCs overwhelm the cytometer, as they make up around 95% of the cells in human whole blood. White blood cells (leukocytes), on the other hand, only make up 0.1-0.2% of cells, and lymphocytes between about 15 to 50% of leukocytes.
The cell mixture is then analyzed on a cell sorter such as a BD FACSAria.
From: https://commons.wikimedia.org/wiki/File:Fluorescence_Assisted_Cell_Sorting_%28FACS%29_B.jpg
The cells pass in single file past one or more laser beams, which excite the dyes and cause them to fluoresce at a certain wavelength. The user can then use gating to select the combination and intensity of colors they are interested in, and when a cell meets the criteria, it is given an electrical charge, and electro magnets direct it into a collection container.
The following is multiple choice question (with options) to answer.
What type of cells make up about one quarter of all white blood cells? | [
"lymphocytes",
"erythrocytes",
"Fat",
"tumors"
] | A | Lymphocytes ( Figure below ), a type of white blood cell, are the key cells of an immune response. There are trillions of lymphocytes in the human body. They make up about one quarter of all white blood cells. Usually, fewer than half of the body’s lymphocytes are in the blood. The rest are in the lymph, lymph nodes, and lymph organs. |
SciQ | SciQ-578 | newtonian-mechanics, classical-mechanics, gravity, forces, astrophysics
Title: Universal gravity at small distance Could it be that there is simply a maximum gravitational force that two bodies of finite mass can exert on one another? This would occur at $r=0$, so maybe there is some really really really small $a$ in the universal gravity equation, making it
$$F=G\frac{m_1m_2}{r^2+a}$$
If $a$ was small enough, it would only become apparent at extremely small distances. So as $r$ got smaller, the force would approach it's actual maximum which would be proportional to the two masses rather than just approaching infinity.
Feel free to tell me in layman's terms why that idea is no good, but I haven't had calculus in like 15 years so I doubt I will understand anything too complex. Folks are looking for non-Newtonian gravity. The experimental gravity group at U. Washington have really been the leaders in the field over the past ten years; they have some nice review papers available for free.
Because of the way that short-range forces work in quantum mechanics, we expect that a short-range gravitational interaction would produce a Yukawa potential,
\begin{align*}
\Phi = -\frac{GMm}{r}
\left(
1 + \alpha e^{-r/\lambda}
\right).
\end{align*}
The first term is just the ordinary Newtonian potential. In the second term, $\alpha$ sets the strength of the interaction and $\lambda$ is its length scale. The constraints depend on both $\alpha$ and $\lambda$. As of 2007, it was possible to rule out an interaction with $\alpha=1$ and $\lambda$ > 55 μm.
I expect that the existing data sets constraints on your $a$. If you go to do arithmetic with it, you'll probably want to redefine your $a$ to have units of length rather than length$^2$.
The following is multiple choice question (with options) to answer.
The mass of the objects and the distance between them affect the strength of what universal force? | [
"motion",
"weight",
"states of matter",
"gravity"
] | D | All objects in the universe have a gravitational attraction to each other ( Figure below ). The strength of the force of gravity depends on two things. They are the mass of the objects and the distance between them. The greater the objects’ mass, the greater the force of attraction. As the distance between the objects increases, the force of attraction decreases. |
SciQ | SciQ-579 | zoology, ecology, species-distribution, migration
Title: How do animals end up in remote areas? I was thinking specifically about random marshy water holes on farmers fields. It seems that you can visit just about any one of these and you will find frogs if you look hard enough.
They usually don't seem to be connected to each other. If it were any other land animal I would figure they walk from one spot to another, but in the case of frogs, I don't imagine their range is very vast. But often these marshy spots can be separated by fairly large distances to a frog.
So this brings me to my question: how do each of these spots end up with frogs in them? I don't imagine a frog is going to go hopping over a hill to get to a marsh on the other side, is it? This question pertains to organism dispersal, which is a very active field of study with relation to it's impact on conservation efforts. Much of what I will say below has been covered in this wiki.
Definition: From the Wiki
Technically, dispersal is defined as any movement that has the
potential to lead to gene flow.
It can be broadly classified into two categories:
Density dependent dispersal
Density independent dispersal
The question of frogs and fishes both refer to Density independent dispersal, while an example of density independent dispersal can be the competition for habitat space between big cats and humans (this is a WWF pdf)
From the wiki:
Density-independent dispersal
Organisms have evolved adaptations for dispersal that take advantage
of various forms of kinetic energy occurring naturally in the
environment. This is referred to as density independent or passive
dispersal and operates on many groups of organisms (some
invertebrates, fish, insects and sessile organisms such as plants)
that depend on animal vectors, wind, gravity or current for dispersal.
Density-dependent dispersal
Density dependent or active dispersal for many animals largely depends
on factors such as local population size, resource competition,
habitat quality, and habitat size.
Currently, some studies suggest the same.
This study in particular studied the movement and habitat occupancy patterns within ephemeral and permanent water bodies in response to flooding. They found that during flooding these frogs moved out to flooded ephemeral water bodies and later on moved back again to the permanent ones.
Other suggested readings for those highly interested in the subject may include this (a phd thesis) and this (a project report)
The following is multiple choice question (with options) to answer.
Without the dominant disturbance, the fire-adapted species are usually outcompeted and biodiversity is what? | [
"immaterial",
"reduced",
"increased",
"unaffected"
] | B | |
SciQ | SciQ-580 | cancer, mutations
Here is another great paper that specifically addresses your question, linking increased cell division with the accumulation of both significant and insignificant mutations, which over time, lead to an accumulation of mutations needed for cancer to develop.
The following is multiple choice question (with options) to answer.
Constantly going through some form of growth and repair is a characteristic of all what? | [
"bacteria",
"viruses",
"living things",
"mass"
] | C | |
SciQ | SciQ-581 | electricity, electric-circuits, electric-current, semiconductor-physics
Title: Why does current have to flow in the same direction? If current is just the movement of charged particles, why do the all have to move in the same direction?
For example, if you reverse-bias a diode (connect the positive terminal to the n-type side and the negative terminal to the p-type side), the positive "holes" are attracted to the negative terminal and the electrons are attracted to the positive terminal.
Firstly, if positive holes moving towards the negative terminal corresponds to electrons moving the opposite way (since "holes" aren't real, they're just a lack of electrons). So on both sides of the diode, electrons are moving in the same direction. I don't quite understand how this doesn't correspond to a current flowing.
Not even looking that deep into it, if positive charges are moving one way and negative charges the other, why does it matter if they cross the PN junction? Moving charges = electricity, right?
On top of all this, the battery creates an electric field that goes through all the wires, so why is there no current in the circuit? Electrons don't even move that fast (I've heard drift speed is on the order of cm/s), so "current" is localized in the sense that an electron on one side of a circuit may never even reach the other side. So why aren't localized electric fields enough to create a circuit? All charges don't move in the same direction. It's the net effect that we see. I think you're missing the fact that conventially current was thought to be the flow of positive charges.
Let's consider an example (something less complex than the diode example you've mentioned)
Consider an area element of a conductor and view it in a direction along its plane.
Let there be both positive and negative charges (yes, these are electrons (for a metallic conductor) but for the time being let them be positive and negative charges) to the left and right of the element.
The following is multiple choice question (with options) to answer.
Positive charges move in the direction of the electric field and the same direction as what current? | [
"alternating current",
"direct current",
"conventional current",
"relativity current"
] | C | Figure 20.4 Current I is the rate at which charge moves through an area A , such as the cross-section of a wire. Conventional current is defined to move in the direction of the electric field. (a) Positive charges move in the direction of the electric field and the same direction as conventional current. (b) Negative charges move in the direction opposite to the electric field. Conventional current is in the direction opposite to the movement of negative charge. The flow of electrons is sometimes referred to as electronic flow. |
SciQ | SciQ-582 | redox, titration
Title: What are the products for the redox reaction HCl + SnCl₂ + KMnO₄? In the redox reaction, where $\ce{HCl}$ is the excess reactant do these reactions produce following half reactions?
\begin{aligned}
(1)&&\ce{SnCl2 &-> Sn^{4+} + 2e-}\\
(2)&&\ce{8H+ + KMnO4 + 5e- &-> Mn^{2+} + 4H2O}
\end{aligned}
Where does the $\ce{HCl}$ come into play here, or do you consider it at the end when you have a final equation?
This is a redox reaction where $\ce{KMnO4}$ was added to $\ce{HCl}$ and $\ce{SnCl2}$ (hydrochloric acid was simply used as an excess reagent) $$\ce{KMnO4 + SnCl2 + HCl -> KCl + MnCl2 + SnCl4 + H2O}$$
Oxidation states are for reactants:
\begin{aligned}\ce{
K &= +1\\
Mn &= +7\\
O &= -2 \\
Sn &= +2\\
Cl &= -1\\
H &= +1\\
}\end{aligned}
Oxidation states for products:
\begin{aligned}\ce{
K &= +1\\
Cl &= -1\\
Mn &= +2\\
Sn &= +4\\
H &= +1\\
O &= -2\\
}\end{aligned}
This is a redox reaction carried out in acidic solution. $\ce{SnCl2}$ and $\ce{KMnO4}$ are titrated with hydrochloric acid. What is being oxidized and what is being reduced? Potassium is being reduced, magnesium and tin are oxidized.
Let's write out our half reactions:
\begin{aligned}\ce{
HCl + SnCl2 &-> SnCl\\
HCl + KMnO4 &-> MnCl2 + KCl + H2O
}\end{aligned}
The following is multiple choice question (with options) to answer.
Redox reactions, like other chemical reactions, begin with a product and end with what? | [
"plasma",
"stimulant",
"decomposition",
"reactant"
] | D | Learn to balanced simple redox reactions by inspection. Learn to balance complex redox reactions by the half reaction method. Use the solvent, or parts of it, as a reactant or a product in balancing a redox reaction. Balancing simple redox reactions can be a straightforward matter of going back and forth between products and reactants. For example, in the redox reaction of Na and Cl2:. |
SciQ | SciQ-583 | condensed-matter, pressure, temperature
$$\alpha = \frac{1}{V}\left(\frac{\partial V}{\partial T}\right)_P $$
Therefore the result is:
$$\left(\frac{\partial T}{\partial P}\right)_S = \frac{T V\alpha}{C_P}$$
In terms of the specific heat capacity (per unit mass) $c_P$ this is:
$$\left(\frac{\partial T}{\partial P}\right)_S = \frac{T\alpha}{\rho c_P}$$
where $\rho$ is the density. For water at 20 C this is about $1.45\times 10^{-8}\frac{K}{\text{Pa}}$, so 1000 bar pressure will raise the temperature by about 1.45 C.
The following is multiple choice question (with options) to answer.
How does alcohol expand over a wide range of temperatures? | [
"variably",
"uniformly",
"erratically",
"exponentially"
] | B | The red liquid in this thermometer is alcohol. Alcohol expands uniformly over a wide range of temperatures. This makes it ideal for use in thermometers. |
SciQ | SciQ-584 | evolution
bacteria
cyanobacteria
archaea
protists
fungi
algae
plants
nematodes
arthropods
vertebrates
Bacterial and archaean colonisation
The first evidence of life on land seems to originate from 2.6 (Watanabe et al., 2000) to 3.1 (Battistuzzi et al., 2004) billion years ago. Since molecular evidence points to bacteria and archaea diverging between 3.2-3.8 billion years ago (Feng et al.,1997 - a classic paper), and since both bacteria and archaea are found on land (e.g. Taketani & Tsai, 2010), they must have colonised land independently. I would suggest there would have been many different bacterial colonisations, too. One at least is certain - cyanobacteria must have colonised independently from some other forms, since they evolved after the first bacterial colonisation (Tomitani et al., 2006), and are now found on land, e.g. in lichens.
Protistan, fungal, algal, plant and animal colonisation
Protists are a polyphyletic group of simple eukaryotes, and since fungal divergence from them (Wang et al., 1999 - another classic) predates fungal emergence from the ocean (Taylor & Osborn, 1996), they must have emerged separately. Then, since plants and fungi diverged whilst fungi were still in the ocean (Wang et al., 1999), plants must have colonised separately. Actually, it has been explicitly discovered in various ways (e.g. molecular clock methods, Heckman et al., 2001) that plants must have left the ocean separately to fungi, but probably relied upon them to be able to do it (Brundrett, 2002 - see note at bottom about this paper). Next, simple animals... Arthropods colonised the land independently (Pisani et al, 2004), and since nematodes diverged before arthropods (Wang et al., 1999), they too must have independently found land. Then, lumbering along at the end, came the tetrapods (Long & Gordon, 2004).
Note about the Brundrett paper: it has OVER 300 REFERENCES! That guy must have been hoping for some sort of prize.
References
The following is multiple choice question (with options) to answer.
How many years ago may the earliest fungi have evolved? | [
".350 million",
"500 million",
".250 million",
"600 million"
] | D | The earliest fungi may have evolved about 600 million years ago. |
SciQ | SciQ-585 | ros, rostopic, ros-indigo, joint-state
I know this is documented somewhere more officially - I'll try to get a link.
As gvdhoorn mentioned, I made a mistake here, either the gripper joints are there, or the other joints are there.
This is expected behavior. See this Wiki for the reference.
The following is multiple choice question (with options) to answer.
What are the bones in partly movable joints held in place by? | [
"collagen",
"cartilage",
"tendons",
"socket"
] | B | Partly movable joints allow only very limited movement. Bones at these joints are held in place by cartilage. The ribs and sternum are connected by partly movable joints. |
SciQ | SciQ-586 | human-anatomy
Title: Why is a penis an organ? According to Wikipedia an "An organ is a group of tissues with similar functions". I don't know anything about anatomy but it doesn't seem to me that a penis can be delimited somewhere to form a "group". Therefore I do not understand why a penis is considered an organ.
Can you explain it to me ? Frankly, that's a terrible definition by Wikipedia.
Merriam-Webster defines an organ as:
a differentiated structure (such as a heart, kidney, leaf, or stem) consisting of cells and tissues and performing some specific function in an organism
or
bodily parts performing a function or cooperating in an activity
The important defining feature of an organ is not that the tissues have similar functions but that, together, the tissues comprise a functional whole that achieves some end goal.
For the penis, it consists of multiple tissues with different functions:
(from https://www.ncbi.nlm.nih.gov/books/NBK525966/figure/article-20668.image.f1/ - original from Gray's Anatomy)
The different tissues pictured here: the fibrous envelope, the corpora cavernosa, the septum pectiniforme, the urethra and blood vessels, the nervous tissue in the skin: all of these tissues have different individual functions: structural, erectile, carrying urine or semen, etc.
The key that unifies them into an organ is that the functions of the penis at the organism level (principally sexual function) are not served by any of these tissues alone, but rather by their combination in a full structure: an organ.
Ultimately, organ definitions are somewhat opinion-based: people are lumpers and splitters, so you might find conflicting definitions for which groupings of tissues reflect distinct organs, but I think by most standards you would find the penis to be considered a distinct organ, affiliated with but distinct from the primary sex organs and associated glands.
The following is multiple choice question (with options) to answer.
Sepals, petals, stamens, and carpels are what kind of organs? | [
"marine",
"animal",
"floral",
"reproductive"
] | C | |
SciQ | SciQ-587 | botany, plant-physiology
Title: Can any plant regenerate missing tissue? I have not yet found a plant that, when an insect eats a hole in one of its leaves, it can regenerate the lost tissue. Many plants will grow a new stem if the old one is cut, but it is not a perfect regeneration, and has no likeness in form to the previous stem. Are there any plants that can, even to a degree, regenerate missing tissue? In general, plant cells only undergo differentiation at special regions in the plant known as meristems. Two of the primary types of meristem are the root apical meristem (at the tips of roots) and the shoot apical meristem (at shoot tips)^. Within the shoot apical meristem the plant cells divide and begin to differentiate into different cell types (such as different cells of the leaf, or vascular cells). Later growth (of, say, a leaf) is largely a result of cell expansion (although cell division does still occur, but drops off as the leaf expands). Therefore, if you punch a hole in a leaf, it probably won't be filled in because the cells in that leaf have finished growing and dividing.
However, as a shoot grows, more meristems are created. These are found in the axillary buds, just above where the leaf meets the stem. The meristems in the axillary buds can grow to form branches. Different plants obviously make different numbers of branches, but there is a common control mechanism known as apical dominance, where the meristem at the tip of the shoot suppresses the growth of the lower axillary buds. This is why a shoot with no branches can be made to grow branches by cutting off the tip (gardeners often do this to make "leggy" plants more bushy).
All of that was a long explanation to say, no, a plant doesn't normally^^ regenerate in the sense of filling in cells that have gone missing. However, if you cut off a shoot, the next remaining bud might begin to grow and, in a sense, replace the part that was lost. In that case, an existing bud is recruited to form a new branch and replace lost functionality, but I wouldn't say that qualifies as regenerating missing tissue.
^There are other types of meristem as well.
The following is multiple choice question (with options) to answer.
How do most growing plant cells expand? | [
"through water uptake",
"through photosynthesis",
"through germination",
"through cell respiration"
] | A | |
SciQ | SciQ-588 | computational-chemistry, software, notation, cheminformatics
H 2.842563000 1.687658000 0.858736000
H 2.884117000 2.439555000 -0.786611000
H 0.678948000 5.023670000 -0.395042000
H 0.990357000 3.982867000 -1.828352000
H -0.686746000 4.150262000 -1.160750000
H -4.302108000 2.573768000 2.564446000
H -3.673500000 1.421270000 3.794842000
H -2.700063000 2.872570000 3.312044000
H -4.742112000 0.063129000 1.051704000
H -3.359638000 -1.014277000 0.656570000
H -3.871382000 -0.807607000 2.379049000
The following is multiple choice question (with options) to answer.
What is the common term for the chemical formula h 2 0? | [
"air",
"hydrogen",
"water",
"oxygen"
] | C | Water is an amazing molecule. It has a very simple chemical formula, H 2 O. It is made of just two hydrogen atoms bonded to one oxygen atom. Water is remarkable in terms of all the things it can do. Lots of things dissolve easily in water. Some types of rock can even completely dissolve in water! Other minerals change by adding water into their structure. |
SciQ | SciQ-589 | organic-chemistry, reactivity
Title: Do Grignard reagents react with amides? Clearly the amide will be unreactive given the poor quality of the leaving group and poor electrophilcity due to delocalization. However, does it react with organolithiums for example? Amides will react with three equivalents n-butyllithium to give nitriles via geminal lithium oxyimide intermediates (J. Org. Chem., 1967, 32 (11)). n-butyllithium is a strong enough base to deprotonate the molecule twice at nitrogen and once alpha to the carbonyl group. Grignard reagents may well behave similarly.
I do not think this is a particularly useful transformation though because n-butyllithium is a rather indiscriminate reagent. There are a wide range of other methods available - see this paper if you're interested.
In the special case of a N,O-dimethylhydroxyamide, you can make ketones using either.
The following is multiple choice question (with options) to answer.
What kind of reaction is needed to prepare amides? | [
"lipophilic acid reaction",
"oxidize acid reaction",
"amino acid reaction",
"carboxylic acid reaction"
] | D | Amides are prepared by the reaction of a carboxylic acid with ammonia or an amine. |
SciQ | SciQ-590 | botany, reproduction
Title: Are the seeds in a single capsicum fruit genetically identical? Hopefully not a too-basic question for the venue. I'm a chile pepper growing hobbyist and have spent some time searching around and reading up on pepper (angiosperm) reproduction, but I'm not getting a clear picture of the details.
It seems like flowers have multiple ovules and it seems like one pollen-grain landing on the stigma leads to fertilization of a single ovule. And it seems like that process produces a single seed.
But that fertilization also prompts fruit growth and flower death and capsicum fruits have many seeds, never just one (that I've ever seen).
So, does each seed have a potentially different father? Or are the multiple seeds generated through a reproductive/cloning process that I'm not seeing written about? Or something else? No, the seeds are not genetically identical. Each seed come from the fertilization of an ovum with a sperm from a separate pollen grain. Since each pollen grain can come from a different plant, the seeds will generally differ from one another.
Additionally, even ova from a single plant will not usually be genetically identical to one another. This is because the process that creates the ova (meiosis) shuffles the genes of the parent plant on then places only half into the ovum. The same kind of shuffling goes on in the creation of pollen grains.
In the chili pepper genus (Capsicum), plants are predominantly self-pollinating. This means the majority of the pollen for the seeds in a fruit will come from the very same plant. This generally reduces the amount of variation seen in the offspring compared to complete cross-plant pollination. Some cross-pollination can nevertheless occur if there are other varieties in the neighborhood. The fruit will not show the effects of the new genetic combinations present in its seed, but only a plant grown from the seed will make the differences evident.
The following is multiple choice question (with options) to answer.
What is the process by which the egg is fertilized by the pollen of the same flower? | [
"self realization",
"self pollination",
"self condensation",
"self formation"
] | B | In self-pollination , the egg is fertilized by the pollen of the same flower. |
SciQ | SciQ-591 | plant-anatomy
Title: Are bryophyte sporangia multicellular? My research on the matter can be summarized in a sentence: "It [sporangium] can be composed of a single cell or can be multicellular" (Source: https://en.wikipedia.org/wiki/Sporangium). Yet there shouldn't be a reply placed between "They are" and "They aren't" test options, speaking of "Are bryophyte sporangia multicellular?". A link to the source where I could ascertain whether the bryophyte sporangia is multicellular (if I could ascertain) is highly appreciated. In Embryophyta (land plants), including bryophytes, the sporangium is usually a multicellular structure.
Perhaps you meant to ask about the number of spore mother cells (SMCs) in each sporangium? That varies across groups. In bryophytes, each sporangium has many SMCs, and accordingly produces a large number of spores. (Contrast this with angiosperms, where a megasporangium [called an ovule] has only one megaspore mother cell.)
References and further reading:
https://courses.lumenlearning.com/boundless-biology/chapter/bryophytes/
https://www.britannica.com/science/plant-development
Image attribution:
By LadyofHats. (Public domain;
https://commons.wikimedia.org/wiki/File:Hornwort_structures.jpg)
The following is multiple choice question (with options) to answer.
In moss, what becomes elongated to elevate the capsule to enhance spore dispersal? | [
"sera",
"seta",
"risa",
"porta"
] | B | |
SciQ | SciQ-592 | = push-ups / seconds in air is close 340.1... { 450nm } * { f } = { 450nm } * { f } = { 450nm *... Page, or Hz for short bin numbers ( upper levels ) the... Is hit on one end with a speaker bolted to it is n't a concept 's! Calculate the frequency and vice versa vibrational frequency can easily be changed when dial! End with a period of a particular value occurs enrolling in a that... Will show a Sine wave that can be measured in seconds two years of college and save thousands your... Waves that pass a fixed point in unit time divided by a count of all values write our frequencies units. N'T measure something like push-ups in 30 seconds that repeats has a master degree! { 45Hz } =20,250nm/s < =20.25um/s } and the time it takes to do just one.! The 42 seconds per lap through some practice problems the velocity of life... The calculation can be applied to many situations Mean = 2 + 10 + 12 + 8 + 14. Diameter, is the frequency in hertz even if it is an essential feature engines... 1/2 inch in diameter, is the height from highest to lowest points and divide that by 2 your blocker. Means they are related like this: if you are just asked for ,., Types & uses, Mass and Weight: Differences and Calculations, 83,000... Event to occur or education level 83,000 lessons in all major subjects, { courseNav.course.mDynamicIntFields.lessonCount... At B2-B10 and use the first two years of college and save thousands off degree. Something repeats attend yet from a frequency associated with it measurement we use the fact that period is also inverse. Like this: Essentially, anything that repeats has a master 's degree physics. For many people it probably has something to do just one lap how to find frequency measurement! Many situations to connect it to a given wavelength college you want to yet. In how to find frequency proportion of the system frequency is a measure of cycles second! The 1 second of period or from any point to the trough ) an for... To 60 seconds we can see RPM represents a frequency and period can be to! One lap Mean
The following is multiple choice question (with options) to answer.
What is the base unit that frequency is typically measured in? | [
"hertz",
"volume",
"watt",
"degrees"
] | A | The frequency , , is the number of cycles an object goes through in 1 second. Frequency is measured in Hertz (Hz). 1 Hz = 1 cycle per sec. |
SciQ | SciQ-593 | biochemistry, metabolism
The second system, glycolysis, simply refers to the breakdown of carbohydrates (e.g. glucose) to resynthesize ATP from the energy stored in those carbohydrates. Your muscles contain a buffer of glycogen, approx. 300~ gr for the average Joe (give or take). The glycogen can be broken down to glucose-6-phosphate, which can then enter glycolysis. The glucose-6-phosphate is broken down to 2 pyruvate and yields 3 ATP netto (2 when derived from glucose, rather than glycogen, due to a first enzymatic step which requires 1 ATP). The enzymatic steps of glycolysis are controlled by ATP, AMP, ADP and other factors, factually integrating the energy status of the muscle (primarly through allosteric regulation of enzymes, especially phosphofructokinase).
The third system, the oxidative system, refers to the breakdown of carbohydrates and fatty acids, requiring oxygen to 'burn' them (citric acid cycle). The yield of this is much higher than for glycolysis, but the process is way slower.
In essence, all are regulated by the concentration of substrates and products, as well as through allosteric regulation (binding of a molecule at a different site, inhibiting or activating the enzyme, often by intermediates of the pathways themselves). Additionally, there is some long-term regulation through gene expression (e.g. up- or down-regulating expression of genes involved in these pathways), mostly by hormones.
Edit:
Well, I guess this is described in any basic biochemistry book (I'm very fund of the book 'Fundamentals of Biochemistry: Life at the Molecular Level'). If you want to see a description of these energy systems in a more exercise related context (since you were aiming at myocytes) I suggest reading Strength and Condition: Biological Principles and Practical Applications from Marco Cardinale et al., and the NSCA book Essentials of Strength and Conditioning.
The following is multiple choice question (with options) to answer.
Controlling muscles and maintaining balance are just two of the roles of what system? | [
"digestive system",
"electrical system",
"nervous system",
"bacterial system"
] | C | Controlling muscles and maintaining balance are just two of the roles of the nervous system. The nervous system also lets you:. |
SciQ | SciQ-594 | 1)the average velocity,Average Velocity =(" Total Displacement ")/(" Total Time ")Average Velocity =(d(b)-d(a))/(b-a)2)we ... See the full answer
The following is multiple choice question (with options) to answer.
Displacement divided by time is equal to the average what? | [
"force",
"acceleration",
"speed",
"velocity"
] | D | Average velocity is displacement divided by time. |
SciQ | SciQ-595 | biochemistry
Title: Why can't amylase break down glycogen? Amylase is an enzyme that breaks down starch in the form of amylopectin and amylose. Both amylose and amylopectin are formed by alpha glucose joined together by (1-4) and (1-6) glycosidic bonds. Glycogen is no exception, just that it has more branching. However, why is it that a google search shows that it is hydrolyzed by Glycogen Phosphorylase rather than amylase? Also, how can amylase digest both (1,6) and (1,4) glycosidic bonds?
Any help would be greatly appreciated. At an approximation the active sites of enzymes can be considered as having two aspects. The first relates to the catalysis — in this case the breaking of the glycosidic linkage. The second relates to binding the substrate. This review of the α-amylases by MacGregor et al. shows that there is a range of a-amylases, differing in this latter respect — their substrate specificity. In general there are binding sites for a varying numbers of glucose residues at either side of the bond being cleaved. This is shown in Fig. 3 of that review:
The important difference in the structure of glycogen and starch (amylopectin) — seldom mentioned in general biochemical or biology texts — is their patten of branching:
As this previous answer of mine to a different question explains, this results in a globular structure for glycogen granules in which only the ends of the chains are accessible. (The image below, from Protopedia, illustrates this better, especially if you imagine it in three dimensions.)
The following is multiple choice question (with options) to answer.
The complete hydrolysis of starch yields what? | [
"insulin",
"sucrose",
"glutamate",
"glucose"
] | D | Both amylopectin and glycogen contain branch points that are linked through α-1,6linkages. These branch points occur more often in glycogen. Dextrins are glucose polysaccharides of intermediate size. The shine and stiffness imparted to clothing by starch are due to the presence of dextrins formed when clothing is ironed. Because of their characteristic stickiness with wetting, dextrins are used as adhesives on stamps, envelopes, and labels; as binders to hold pills and tablets together; and as pastes. Dextrins are more easily digested than starch and are therefore used extensively in the commercial preparation of infant foods. The complete hydrolysis of starch yields, in successive stages, glucose:. |
SciQ | SciQ-596 | surface-tension
Title: When does a liquid 'wet' a solid surface? What is exactly meant when it is said that a liquid wets a solid surface. Has it got only to do with the contact angle ? The process of wetting of a solid surface is better explained with cohesive and adhesive forces. Wetting of a solid surface by a liquid means the liquid molecules succeeded in maintaining a contact with the surface through the inter molecular attractive forces. You should see that every liquid may not stick on to a given surface and similarly every surface may not get by a given liquid.
A liquid has it's own inter molecular force of attraction that maintains it's continuity. Such forces existing between same type of molecules is called cohesive force. Now if there is some inter molecular attractive forces between different molecules then it is called adhesive force. When the cohesive force between the water molecules is greater than the adhesive force of water molecules with the solid molecules, then it cannot stick on the surface. You can see a drop of water on such a surface (hydrophobic) forms a round ball and go in crazy directions. So there will be no wetting. Now in some hydrophilic surfaces, the adhesive force between the liquid and solid molecules dominate and the liquid molecules stick on to the surface. This makes the surface wet.
So the degree of wetting is determined by a force balance between adhesive and cohesive forces.
The contact angle which you mentioned and as shown in the figure depends on the balance between the adhesive and cohesive forces. So one could say that the degree of wetting depends on the angle of contact.If the adhesive forces dominate, then the drop spreads out on the surface, thereby decreasing the angle of contact. In such case, the wetting will be higher. If the cohesive forces dominate, the angle increases as the drop forms a bubble or round up into a spherical body which means the degree of wetting will be low. Thus the contact angle provides an inverse measure of wettability.
The following is multiple choice question (with options) to answer.
What term describes an imbalance of attractive forces between liquid molecules at the surface of a liquid? | [
"obsolute tension",
"surface tension",
"molecular tension",
"currents tension"
] | B | Surface tension is an imbalance of attractive forces between liquid molecules at the surface of a liquid. |
SciQ | SciQ-597 | zoology
Capybara, rabbits, hamsters and other related species do not have a complex ruminant digestive system. Instead they extract more nutrition from grass by giving their food a second pass through the gut. Soft fecal pellets of partially digested food are excreted and generally consumed immediately. Consuming these cecotropes is important for adequate nutritional intake of Vitamin B12. They also produce normal droppings, which are not eaten.
Young elephants, pandas, koalas, and hippos eat the feces of their mother to obtain the bacteria required to properly digest vegetation found on the savanna and in the jungle. When they are born, their intestines do not contain these bacteria (they are completely sterile). Without them, they would be unable to obtain any nutritional value from plants.
Eating garbage and human feces is thought to be one function of dogs during their early domestication, some 12,000 to 15,000 years ago. They served as our first waste management workers, helping to keep the areas around human settlements clean. A study of village dogs in Zimbabwe revealed that feces made up about 25% of the dogs’ overall diet, with human feces making up a large part of that percentage.
Coprophagia
Daily rhythms of food intake and feces reingestion in the degu, an herbivorous Chilean rodent: optimizing digestion through coprophagy
Coprophagia as seen in Thoroughbred Foals
The following is multiple choice question (with options) to answer.
In mammals, four specialized types of what serve to cut, tear, and grind food? | [
"teeth",
"spines",
"scales",
"plates"
] | A | Mammalian teeth are also important for digestion. The four types of teeth are specialized for different feeding functions, as shown in Figure below . Together, the four types of teeth can cut, tear, and grind food. This makes food easier and quicker to digest. |
SciQ | SciQ-598 | human-anatomy, human-physiology, blood-circulation, physiology
Title: Common site for atherosclerosis My book( textbook of anatomy abdomen and lower limb 2nd edition - by vishram Singh pg.no:286) says:
Acute arterial occlusion: It is mostly caused by embolism or thrombosis. It usually occurs in the femoral artery where it gives off the profunda femoris artery.
The following is multiple choice question (with options) to answer.
Atherosclerosis and coronary heart disease are examples of what type of body system disease? | [
"connective system",
"digestive system",
"excretory system",
"cardiovascular system"
] | D | Diseases of the cardiovascular system are common and may be life threatening. Examples include atherosclerosis and coronary heart disease. A healthy lifestyle can reduce the risk of such diseases developing. This includes avoiding smoking, getting regular physical activity, and maintaining a healthy percent of body fat. |
SciQ | SciQ-599 | zoology
Title: What is right below skin? I was skinning a gopher so my cat can eat it (it was a pest and we didn't want to waste it). I thought its organs would fall out and make a mess, but that didn't happen. There was this sticky, transparent substance that surrounded its insides. What is this casing called? My dad said it was mucus but that isn't specific enough since there is mucus inside the stomach so I don't think they are the same.
I think this casing is found in all multicellular animals but I couldn't be sure. Based on your reference to organs falling out and the overall description, I presume you're thinking of the abdominal cavity primarily, so there you'd be looking at the peritoneum or possibly the serous membranes of other organs (e.g., pleura, pericardium). These are membranous (in the general sense, not as a cell membrane) connective tissues covering the organs found in the abdomen and chest.
Other things you'll find underneath skin would include layers of fat, other connective tissues, muscle.
Here's a labeled image of a mouse dissection from Friedrich, L., Schuster, M., de Celis, M. F. R., Berger, I., Bornstein, S. R., & Steenblock, C. (2021). Isolation and in vitro cultivation of adrenal cells from mice. STAR protocols, 2(4), 100999.:
You might also look for dissections of fetal pigs or cats, which are commonly used in laboratory demonstrations for students (more often cats longer ago, more often fetal pigs these days).
The following is multiple choice question (with options) to answer.
When cats mark their territory by rubbing their face against an object, they deposit chemicals released by what structures? | [
"whiskers",
"taste buds",
"pituitary glands",
"scent glands"
] | D | Some animals deposit chemicals to mark the boundary of their territory. This is why dogs urinate on fire hydrants and other objects. Cats may also mark their territory by depositing chemicals. They have scent glands in their face. They deposit chemicals by rubbing their face against objects. |
SciQ | SciQ-600 | plant-anatomy
Title: Are bryophyte sporangia multicellular? My research on the matter can be summarized in a sentence: "It [sporangium] can be composed of a single cell or can be multicellular" (Source: https://en.wikipedia.org/wiki/Sporangium). Yet there shouldn't be a reply placed between "They are" and "They aren't" test options, speaking of "Are bryophyte sporangia multicellular?". A link to the source where I could ascertain whether the bryophyte sporangia is multicellular (if I could ascertain) is highly appreciated. In Embryophyta (land plants), including bryophytes, the sporangium is usually a multicellular structure.
Perhaps you meant to ask about the number of spore mother cells (SMCs) in each sporangium? That varies across groups. In bryophytes, each sporangium has many SMCs, and accordingly produces a large number of spores. (Contrast this with angiosperms, where a megasporangium [called an ovule] has only one megaspore mother cell.)
References and further reading:
https://courses.lumenlearning.com/boundless-biology/chapter/bryophytes/
https://www.britannica.com/science/plant-development
Image attribution:
By LadyofHats. (Public domain;
https://commons.wikimedia.org/wiki/File:Hornwort_structures.jpg)
The following is multiple choice question (with options) to answer.
Like other bryophytes, moss plants spend most of their life cycle as? | [
"gametophytes",
"spores",
"bacteriophages",
"copepods"
] | A | Like other bryophytes, moss plants spend most of their life cycle as gametophytes. Find the sporophyte in the diagram. Do you see how it is growing on the gametophyte plant?. |
SciQ | SciQ-601 | energy, fuel, environmental-chemistry
Title: Effect of coal and natural gas burning on particulate matter pollution I sometimes hear people talking about how we should replace coal burning plants with natural gas ones, to alleviate the case of particulate matter pollution. What exactly is the difference between coal fuel and natural gas that makes the latter seem "cleaner"?
At the same energy outcome, natural gas produces less carbon dioxide than coal. In a way, natural gas is half way between coal and hydrogen.
Coal produces smelly smoke, solid particles, sulfur dioxide and minor or trace heavy metal pollutants.
It is less known to common people, but power plants burning coal are more significant source of radioactive pollution than nuclear plants. This pollution is very diluted, but rather significant in absolute amount. Coal ash, used in past as a filler for some construction materials, has lead in some cases to significantly increased content of radium-226 in building walls. This radium is a product of long term decay of natural uranium. It further decays while producing radioactive gaseous radon-222, which is dangerous in long term inhalation because of lung cancer. As it stays in lungs as polonium-218 and its decay products.
See e.g. Uranium produced from coal ash
... the uranium concentration in the ash pile is about 150-180 parts per million, about 1/4th of the concentration often thought of as commercially viable for ISL[In Situ Leaching] mining. However, coal ash piles have some physical characteristics that might help overcome that disadvantage since they may be easier to drill and it might be easier to protect the local groundwater from contamination. ...
See Radon in building materials by Czech government agency for radiation protection.
The following is multiple choice question (with options) to answer.
What is a benefit of low sulfur coal over high sulfur coal? | [
"less pollution",
"lower cost",
"less erosion",
"greater enerty"
] | A | Low sulfur coal produces less pollution when burned than high sulfur coal. Name one factor that affects the sulfur content in coal. |
SciQ | SciQ-602 | evolution, ornithology, palaeontology, herpetology, dinosaurs
A few words about pterosaurs
Along with birds and bats, pterosaurs are the other clade of vertebrates capable of powered, flapping flight. Pterosaurs fall within Reptilia (and Diapsida and Archosauria) along with Dinosauria, which includes birds. There are a lot of other extinct lineages in the tree that are not shown, e.g., ornithodirans that are not dinosaurs and not pterosaurs. Pterosaurs and birds share anatomical features that all reptiles, diapsids, archosaurs, and ornithodirans have, which is how we know that they are more closely related to each other than to other groups, like crocodiles. But their flight structures evolved independently and are anatomically distinct fro one another. So pterosaurs are flying reptiles but not flying dinosaurs.
These images might help you understand the above explanation.
The following is multiple choice question (with options) to answer.
Wings of bats and birds serve the same function. which body part should you study to understand ancestral differences? | [
"bones inside wings",
"skin inside wings",
"skull size",
"skin and feathers"
] | A | Wings of bats and birds serve the same function. Look closely at the bones inside the wings. The differences show they developed from different ancestors. |
SciQ | SciQ-603 | heat, materials, carbon-allotropes
Title: Why does diamond conduct heat better than graphite? Our teachers made us accept (without any explanation) that diamond conducts heat better than graphite. What is the reason behind this (alleged) fact? Diamond is one of the best thermal conductors known, in fact diamond is a better thermal conductor than many metals (thermal conductivity (W/m-K): aluminum=237, copper=401, diamond=895). The carbon atoms in diamond are $\ce{sp^3}$ hybridized and every carbon is bonded to 4 other carbon atoms located at the vertices of a tetrahedron. Hence the bonding in diamond is a uniform, continuous 3-dimensional network of $\ce{C-C}$ single (sigma) bonds. Graphite on the other hand is formed from $\ce{sp^2}$ hybridized carbon atoms that form a continuous 2-dimensional sigma and pi bonding network. This 2-dimensional network forms sheets of graphite, but there is little connection between the sheets, in fact, the sheet-sheet separation is a whopping ~3.4 angstroms. This might lead us to suspect that heat conduction in the 2-dimensional sheet of graphite would be superior to diamond, but that heat conduction between graphite sheets would be very low. This is, in fact, an accurate description of thermal conduction in graphite. Thermal conductivity parallel to the graphite sheets=1950, but thermal conduction perpendicular to the sheet=5.7. Therefor, when we consider thermal conduction over all possible directions (anisotropic) diamond would be superior to graphite.
The following is multiple choice question (with options) to answer.
The best thermal conductors are also the best conductors of what, which is also related to the density of free electrons in them? | [
"sound",
"pollution",
"electricity",
"light"
] | C | Note that in Table 14.3, the best thermal conductors—silver, copper, gold, and aluminum—are also the best electrical conductors, again related to the density of free electrons in them. Cooking utensils are typically made from good conductors. |
SciQ | SciQ-604 | botany, plant-physiology
Title: Can any plant regenerate missing tissue? I have not yet found a plant that, when an insect eats a hole in one of its leaves, it can regenerate the lost tissue. Many plants will grow a new stem if the old one is cut, but it is not a perfect regeneration, and has no likeness in form to the previous stem. Are there any plants that can, even to a degree, regenerate missing tissue? In general, plant cells only undergo differentiation at special regions in the plant known as meristems. Two of the primary types of meristem are the root apical meristem (at the tips of roots) and the shoot apical meristem (at shoot tips)^. Within the shoot apical meristem the plant cells divide and begin to differentiate into different cell types (such as different cells of the leaf, or vascular cells). Later growth (of, say, a leaf) is largely a result of cell expansion (although cell division does still occur, but drops off as the leaf expands). Therefore, if you punch a hole in a leaf, it probably won't be filled in because the cells in that leaf have finished growing and dividing.
However, as a shoot grows, more meristems are created. These are found in the axillary buds, just above where the leaf meets the stem. The meristems in the axillary buds can grow to form branches. Different plants obviously make different numbers of branches, but there is a common control mechanism known as apical dominance, where the meristem at the tip of the shoot suppresses the growth of the lower axillary buds. This is why a shoot with no branches can be made to grow branches by cutting off the tip (gardeners often do this to make "leggy" plants more bushy).
All of that was a long explanation to say, no, a plant doesn't normally^^ regenerate in the sense of filling in cells that have gone missing. However, if you cut off a shoot, the next remaining bud might begin to grow and, in a sense, replace the part that was lost. In that case, an existing bud is recruited to form a new branch and replace lost functionality, but I wouldn't say that qualifies as regenerating missing tissue.
^There are other types of meristem as well.
The following is multiple choice question (with options) to answer.
What tissue do clubmosses have that mosses do not? | [
"nuclei",
"chorophyll",
"dioxide tissue",
"vascular tissue"
] | D | Clubmosses can resemble mosses; however, clubmosses have vascular tissue, while mosses do not. |
SciQ | SciQ-605 | human-biology, microbiology
Title: How much weight/volume do microbes occupy within the human body? Microorganisms constitute the bulk of all the biomass on Earth. I weighed myself yesterday, and wondered how much less I would weigh if I were completely free of bacteria and microbes, inside and out.
Approximately how much weight and volume do microbes occupy within the average human body? How were these values obtained? @AlanBoyd's calculations are reasonable, I think the estimate is off though. The human microbome includes other bacteria which are not necessarily E.coli equivalent.
The human microbome projects give estimates that microbes are 1-3% total body mass. i.e. several pounds of bacteria.
The GI tract alone has most of the microbome mass - faeces is ~60% intestinal flora/fauna by dry weight, which for many adults alone must be hundreds of grams at any given moment.
The following is multiple choice question (with options) to answer.
The average human body contains 5,830 g of what? | [
"blood",
"muscle",
"water",
"bacteria"
] | A | The average human body contains 5,830 g of blood. What mass of arsenic is present in the body if the amount in blood is 0.55 ppm?. |
SciQ | SciQ-606 | evolution, species, molecular-evolution, species-distribution, macroevolution
Lalage leucopygialis, L. nigra, and L. sueurii: Species of triller birds that coexist on Sulawesi Island.
The existence of ring species like this can, as biologist Ernst Mayr puts it, illustrate "how new species can arise through 'circular overlap', without interruption of gene flow through intervening populations…" and offers proof of speciation through a method other than allopatric speciation: speciation that happens when two populations of the same species become isolated from each other due to geographic changes.
The following is multiple choice question (with options) to answer.
What type of speciation occurs when groups from the same species are geographically isolated for long periods? | [
"asexual",
"symbiotic",
"allopatric",
"prokaryotic"
] | C | Allopatric speciation occurs when groups from the same species are geographically isolated for long periods. Imagine all the ways that plants or animals could be isolated from each other:. |
SciQ | SciQ-607 | neuroscience, neurophysiology, sensation, hearing, human-ear
Title: Why/how does exposure to noise cause cochlear hair-cell loss? I am trying to understand why listening to loud music - e.g. concerts or earphones at high volume damages hearing.
According to the National Institute on Deafness the cause is physical.
Most NIHL is caused by the damage and eventual death of these hair
cells. Unlike bird and amphibian hair cells, human hair cells don’t
grow back. They are gone for good.
But I don't understand why/how would noise - which should basically lead to higher amplitude waves in the basilar membrane, induce damage and death of these hair cells? There are a number of pathophysiological mechanisms that are thought to underlie noise-induced hearing loss:
Mechanical damage to the delicate cells and supporting structures of the organ of Corti;
Reduced blood flow to the inner ear;
Intense metabolic activity, which increases mitochondrial free radical formation.
Reactive oxygen species (ROS) are highly reactive. They are essential for mitochondrial function to generate energy. However, too many of them damage cellular lipids, proteins, and DNA, and upregulate apoptotic pathways. The observed impaired blood flow to the cochlea can enhance the toxic effects of ROS. Mechanical damage to the delicate hairs and membranes of the hair cells reduces their ability to converge acoustical energy into potential differences.
References
- Le Prell et al., Hear Res (2007); 226(1-2): 22–43
- Kurabvi et al., Hear Res (2017); 349: 129-37
The following is multiple choice question (with options) to answer.
What can damage the hair cells lining the cochlea of the inner ear? | [
"wavering sounds",
"amelodic sounds",
"loud sounds",
"unexpected sounds"
] | C | Loud sounds can damage the hair cells lining the cochlea of the inner ear. Explain how this might affect the ability to hear sound. |
SciQ | SciQ-608 | physical-chemistry
Title: why does adding a non volatile solute not decrease the boiling point? If I add a solute that decreases the bond strength of the pure solvent then wouldn't the solvent molecules evaporate more easily as it has lesser force holding it down now?But in my textbook, it's written that BP always increases when we add a non-volatile solute. Decrease of the solvent activity due its decreased molar fraction is bigger than the solvent activity increase due eventual solvent solute interaction.
So the pressure versus solute molar fraction curve may not be linear as by the Raoult law, but is monotonous.
The following is multiple choice question (with options) to answer.
The boiling point of a solution is higher than the boiling point of the pure solvent, but the opposite occurs with this? | [
"liquidity point",
"evaporation point",
"dissolving point",
"freezing point"
] | D | The boiling point of a solution is higher than the boiling point of the pure solvent, but the opposite occurs with the freezing point. The freezing point of a solution is lower than the freezing point of the pure solvent. Think of this by assuming that solute particles interfere with solvent particles coming together to make a solid, so it takes a lower temperature to get the solvent particles to solidify. This is called freezing point depression. The equation to calculate the change in the freezing point for a solution is similar to the equation for the boiling point elevation:. |
SciQ | SciQ-609 | circulatory-system, lymphatic-system, veins
Title: How does most of lymph get back into the blood stream? (I don't mean the lymphatic system) I once read that it was because of osmotic pressure that it returns to the blood stream, by entering the venules. But why? If lymph originated as plasma how come that the solute concentration is higher in the venule? Doesn't plasma contain solutes such as salts, nutrients, oxygen, etc. ? Technically 'lymph' is used to refer to the fluid found within the lymphatic system. If it's not in the lymphatic system, it is not lymph fluid. Thus, your question is really asking about interstitial fluid or the plasma that was filtered out of blood capillaries.
The answer to your question is based on the Starling equation. Normally fluid leaves a capillary due to a net pressure that favors the interstitium. This net pressure is based on the hydrostatic pressure within the capillary being greater than the interstitial pressure of the surrounding tissues, and the oncotic pressure of the capillary (that draws fluid in) being weaker than the hydrostatic pressure of the capillary (that pushes fluid out). At the venule end of this system, the capillary oncotic pressure is stronger than the capillary hydrostatic pressure, drawing fluid back into the circulatory system.
Remember that albumin is the most important component which establishes the oncotic pressure within a vessel, and that this protein is normally NOT released out of a vessel during filtration. Thus, it passes from the capillary into its corresponding venule directly.
The following is multiple choice question (with options) to answer.
What is the network of vessels and tissues that carry a clear fluid called lymph called? | [
"vessel system",
"cleansing system",
"excretory system",
"lymphatic system"
] | D | The lymphatic system is a network of vessels and tissues that carry a clear fluid called lymph. The lymphatic system ( Figure below ) spreads all around the body and filters and cleans the lymph of any debris, abnormal cells, or pathogens. Lymph vessels are tube-shaped, just like blood vessels, with about 500-600 lymph nodes (in an adult) attached. The lymphatic system works with the cardiovascular system to return body fluids to the blood. The lymphatic system and the cardiovascular system are often called the body’s two "circulatory systems. ". |
SciQ | SciQ-610 | solutions, phase, evaporation
Title: What is the relationship between solutions and changes to states of matter? For example, when liquid water evaporates, my instinct is to say that of course it's become gas, but I'm a bit unsure because, if I understand correctly, evaporation occurs because air dissolves the water, and it's not clear to me whether that counts as a phase change. Intuitively it seems like it should should water dissolves in the air or salt dissolved in water, etc. have different properties before and after being dissolved. And yet, the way I've always heard it explained, phase changes are specifically due to changes in temperature and/or pressure, not due to chemical interactions with another another substance.
On the other hand, from what I remember from chem 101 and 102, when we considered chemical reactions occuring between solids dissolved in a liquid (usually acids and bases dissolved in water), we usually just labeled them as aqueous, meaning "in solution", whereas for non-aqueous substances, we'd label them with the relevant state of matter, solid, liquid, or gas. Does that mean dissolved substances constitute their own state of matter? Or that it's simply not meaningful to talk about the state of the solute independent of the solvent?
I also saw this thread, Is it appropriate to say "solid-in-gas solution" and "liquid-in-gas solution"?, where someone says, "Whenever there is only one phase, but there are two or more chemical species, then you have a solution", which heavily implies there's a fundamental relationship between phase changes and solutions, but it also doesn't seem quite right Water vapour in air is a solution, but not in the same sense as solutions in water.
Water vapour in air is solution in sense of homogenous mixture, where molecules move freely and independently.
Salts in water dissociate (are dissociated by water) to ions. Having a net charge, they form a nonhomogeneous electrostatic gradient.Ions are hydrated by water molecules that have an electric dipole and therefore attracted to the center of such a gradient. So here we see strong interaction and dependent motion.
The following is multiple choice question (with options) to answer.
What is defined as the change of water from its liquid phase to its gaseous phase? | [
"absorption",
"condensation",
"transpiration",
"evaporation"
] | D | |
SciQ | SciQ-611 | radiation, x-rays, cosmic-rays
Wouldn't those different types of waves have different properties?
Matter responds differently to the different wavelengths of photons, due to the increasing energy they carry which is proportional to their frequency and inversely proportional to their wavelength.
The column on the far right gives the energy of the photon. A micron wavelength is in the electron Volt range and can affect molecular distances and cohesion and living matter. Below that the interaction with matter is in bulk, not individual molecules and cells after the Ultraviolet level. The electromagnetic radiation that can affect health is ultraviolet and smaller wavelengths. The smaller the wavelength the larger the possibility of destruction of living cells which is the study of health physics: by, as the frequency increases, heating in depth,breaking of chemical bonds, ionizing, and finally destroying complete cell structures when going to MeV energies.
The following is multiple choice question (with options) to answer.
Radiation, chemicals, and infectious agents are types of what? | [
"mutagens",
"mutations",
"dioxins",
"endogenous"
] | A | Types of mutagens include radiation, chemicals, and infectious agents. |
SciQ | SciQ-612 | optics, visible-light, condensed-matter, superconductivity, quantum-optics
Title: Optical equivalent of a superconductor Is there some material state that can propagate light indefinitely without dissipation or absorption, like superconductors are able to transmit current indefinitely?
If not, then the question is, why not? would some fundamental principle being violated in such a material? As Claudius suggests, vacuum does not absorb. But that is not a material.
You can have light that travels through a material without absorption; that happens in nonlinear optics with self-induced transparency. The full theory behind that is rather involved and you need really high intensities for that. The basic picture is that the front of the light pulse is absorbed and the back of the pulse stimulates emission from all the excited photons. Thus, the back gets to the front and is absorbed and the whole cycle repeats.
The following is multiple choice question (with options) to answer.
What type of matter transmits light without scattering it? | [
"bioluminescent",
"translucent",
"clean",
"transparent"
] | D | Transparent matter is matter that transmits light without scattering it. Examples of transparent matter include air, pure water, and clear glass. You can see clearly through a transparent object, such as the revolving glass doors in the figure, because all the light passes straight through it. |
SciQ | SciQ-613 | thermodynamics, temperature, everyday-life, phase-transition, humidity
Title: Steam from a cup of coffee I observed that, in winter there is more visible steam from a cup of coffee than in summer. Is there any phenomenon taking place here. The amount of water that air can take up before the water creates fog or visible steam depends on temperature. The colder the air, the less water it needs to create fog/steam. It is the same principle when hot air rises, for example when pushed up a mountain and then it starts to cool down drastically --> It will rain.
For more have a look at: Relative humidity in https://en.wikipedia.org/wiki/Humidity
The following is multiple choice question (with options) to answer.
Steam actually consists of tiny droplets of liquid what? | [
"methane",
"water",
"mercury",
"lead"
] | B | Steam actually consists of tiny droplets of liquid water. What you can’t see in the picture is the water vapor that is also present in the air above the spring. Water vapor is water in the gaseous state. It constantly rises up from the surface of boiling hot water. Why? At high temperatures, particles of a liquid gain enough energy to completely overcome the force of attraction between them, so they change to a gas. The gas forms bubbles that rise to the surface of the liquid because gas is less dense than liquid. The bubbling up of the liquid is called boiling. When the bubbles reach the surface, the gas escapes into the air. The entire process in which a liquid boils and changes to a gas that escapes into the air is called vaporization . You can watch an animation of the process at this URL: http://www. visionlearning. com/img/app/library/objects/Flash/VLObject-321-030317040343. swf. |
SciQ | SciQ-614 | machine-learning, classification, algorithms, beginner, multiclass-classification
Finally, you might be facing such a large number of classes that a single classifier model is overwhelmed and you need to approach the problem differently.
For an example of this last case, consider a classifier for images of pets. If it had three classes (cats, dogs, rabbits), then you'd clearly use standard classification approach. Even when classifying by breed - 100s of classes - then this approach still works well enough, as seen in ImageNet competitions. However, once you decide to try and detect the identity of each pet (still technically a class) you hit a problem using simple classifier techniques - in that case the structure of the solution needs more thought. One possible solution is a regression algorithm trained to extract biometric data from the image (nose length, distance between eyes, angle subtended between centre of jaw and ears) and move the classification stage into KNN based on a database of biometric data for observed individuals. This is how some face identifying algorithms work, by mapping images of faces into an easy-to-classify continuous space first (typically using a deep CNN), then using a simpler classifier that scales well across that space.
The following is multiple choice question (with options) to answer.
What mammalian class has the greatest ability to learn? | [
"humans",
"rats",
"apes",
"reptiles"
] | A | In many ways, humans are unique among mammals. For example, we have bigger brains and a greater ability to learn than any other species in the mammalian class. In many ways, however, we are typical of the mammalian order to which we belong. That order is the Primate Order. To fully understand what it means to be human, you need to know more about this fascinating order of mammals. |
SciQ | SciQ-615 | ## Ch112
The aorta carries blood away from the heart at a speed of about 39 cm/s and has a radius of approximately 1.0 cm. The aorta branches eventually into a large number of tiny capillaries that distribute the blood to the various body organs. In a capillary, the blood speed is approximately 0.072 cm/s, and the radius is about 6.2 x 10-4 cm. Treat the blood as an incompressible fluid, and use these data to determine the approximate number of capillaries in the human body.
• solve in the same approach...
The aorta carries blood away from the heart at a speed of about 44 cm/s and has a radius of approximately 1.2 cm. The aorta branches eventually into a large number of tiny capillaries that distribute the blood to the various body organs. In a capillary, the blood speed is approximately 0.071 cm/s, and the radius is about 6.4 x 10-4 cm. Treat the blood as an incompressible fluid, and use these data to determine the approximate number of capillaries in the human body.
Solution:
The volume has to be the same, so:
44cm/s * 1.44pi cm^2 = 199.05 cm^3/s
so x(.071cm/s * pi*.00064^2) = 199.05cm^3/s
x = (44 * 1.44pi)/(.071 * pi * .00064^2) = 2.17869718 * 10^9 capillaries
• The aorta carries blood away from the heart at a speed of about 37 cm/s and has a radius of approximately 1.2 cm. The aorta branches eventually into a large number of tiny capillaries that distribute the blood to the various body organs. In a capillary, the blood speed is approximately 0.069 cm/s, and the radius is about 6.3 x 10^-4 cm. Treat the blood as an incompressible fluid, and use these data to determine the approximate number of capillaries in the human body.
Flow rate = Cross sectional area * speed
Blood flow from the aorta = (pi)(1.2)^2(37) = 167.38 cm^3/sec.
The following is multiple choice question (with options) to answer.
What is the part of the cardiovascular system that carries oxygen-rich blood away from the heart, to the body, and returns oxygen-poor blood back to the heart? | [
"systemic circulation",
"peripheral nervous system",
"molecular circulation",
"somatic system"
] | A | Systemic circulation is the part of the cardiovascular system that carries oxygen-rich blood away from the heart, to the body, and returns oxygen-poor blood back to the heart. Oxygen-rich blood leaves the left ventricle through the aorta. Then it travels to the body's organs and tissues. The tissues and organs absorb the oxygen through the capillaries. Oxygen-poor blood is collected from the tissues and organs by tiny veins, which then flow into bigger veins, and, eventually, into the inferior vena cava and superior vena cava. This completes systemic circulation. The blood releases carbon dioxide and gets more oxygen in pulmonary circulation before returning to systemic circulation. The inferior vena cava returns blood from the body. The superior vena cava returns blood from the head. |
SciQ | SciQ-616 | optics, electromagnetic-radiation, polarization, maxwell-equations
Wrong Guess Update 2:
Ruslan then suggested that the round source I chose may generate unequally widening wave in x and y direction depending on polarization i.e. it maybe not work as expected.
If this guess is correct, the simulation result won't show perfect symmetry even if I remove the cone i.e do the simulation in an empty space. So I simulated the y-polarized light in vacuum without the cone, and the result shows perfect symmetry, so the source seems to work as expected.
The following picture shows how the whole domain looks like in this simulation (formed with 120×120×70 grids):
Pic 12
Here's the result (taken at same place as pic 9):
Pic 13 As mentioned by Ruslan , precisely speaking, what one should do to simulate the unpolarized light is to take an average of the intensity of all the orthogonal polarized light other than just 2 of them. Plane source is a special case because its z-polarized component is quite weak so it won't hurt even if only an average of x and y-polarized component is taken.
But wait, in Pic 4, OP has already taken an average of all 3 component, why he still can't get full rotational symmetry?
The answer is really simple but easy to ignore: the grid isn't dense enough, so it has formed a not-really-round cone.
After halving the grid size (with other condition remaining the same as Pic 9 and Pic 11), we got the following result:
y-polarized light (with same condition as Pic 9, except for a denser grid):
Pic 14
Supposed unpolarized light (with same condition as Pic 11, except for a denser grid):
Pic 15
z-polarized light:
Pic 16
Light intensity here is in fact very weak, the simulation result of passing rate is about 0.08%. BTW, grids for this simulation still seems to be not dense enough, but it's not a big deal.
To avoid any possible confusion, here is a more accurate simulation result of the z-polarized case:
z-polarized light (with same condition as Pic 16, except for a denser grid, $\Delta x=\Delta y=\Delta z=12.5 nm$):
Pic 17
The following is multiple choice question (with options) to answer.
What causes polarization in a neutral object? | [
"separation of charges",
"combining of charges",
"signaling of charges",
"meaning of charges"
] | A | Charging by Induction It is not necessary to transfer excess charge directly to an object in order to charge it. Figure 18.13 shows a method of induction wherein a charge is created in a nearby object, without direct contact. Here we see two neutral metal spheres in contact with one another but insulated from the rest of the world. A positively charged rod is brought near one of them, attracting negative charge to that side, leaving the other sphere positively charged. This is an example of induced polarization of neutral objects. Polarization is the separation of charges in an object that remains neutral. If the spheres are now separated (before the rod is pulled away), each sphere will have a net charge. Note that the object closest to the charged rod receives an opposite charge when charged by induction. Note also that no charge is removed from the charged rod, so that this process can be repeated without depleting the supply of excess charge. Another method of charging by induction is shown in Figure 18.14. The neutral metal sphere is polarized when a charged rod is brought near it. The sphere is then grounded, meaning that a conducting wire is run from the sphere to the ground. Since the earth is large and most ground is a good conductor, it can supply or accept excess charge easily. In this case, electrons are attracted to the sphere through a wire called the ground wire, because it supplies a conducting path to the ground. The ground connection is broken before the charged rod is removed, leaving the sphere with an excess charge opposite to that of the rod. Again, an opposite charge is achieved when charging by induction and the charged rod loses none of its excess charge. |
SciQ | SciQ-617 | cell-biology, hematology, red-blood-cell
Title: Why are red blood cells considered to be cells? Wikipedia states that a cell is
the basic structural, functional and biological unit of all known living organisms. Cells are the smallest unit of life that can replicate independently.
It then goes on to state that
All cells (except red blood cells which lack a cell nucleus and most organelles to accommodate maximum space for hemoglobin) possess DNA.
Then why are red blood cells still considered cells, while they can't replicate? Is the definition on Wikipedia just a bad definition? Or are red blood cells wrongly considered cells, but remain so for historical reasons? Or are they considered cells for some other reason, such as this answer which states that red blood cells do contain a nucleus at some point? A very good question, and it is most likely because of the last option. It had a nucleus for part of its life. After the RBC jettisons its nucleus, it still remains very metabolically active for approximately 3 months. It maintains its cell membrane integrity, it metabolizes glucose, it interacts constantly with its environment, numerous cellular functions and structure remain intact... It is extremely specialized for a primary purpose, and no longer requires the nucleus to provide more proteins. It has limited capacity to heal from injury, so it has a limited life span.
Speculation: I wonder if it might lose the nucleus early on so that when it is destroyed in the spleen at the end of its life as RBCs are, the spleen macrophages are not overwhelmed with additional processing of nucleic acids? Macrophage type cells are already working hard in there to clear infectious agents and some immune cells from the blood.
The following is multiple choice question (with options) to answer.
Cells in blood include red blood cells, white blood cells, and what? | [
"protons",
"platelets",
"plasmids",
"droplets"
] | B | Cells in blood include red blood cells, white blood cells, and platelets. |
SciQ | SciQ-618 | electrochemistry, home-experiment, crystal-structure
Title: Copper (II) Acetate from 5% vinegar + salt, electrochemically I'm trying to create Copper (II) Acetate crystals, but in these times of Coronavirus it's difficult to come by hydrogen peroxide. I could be patient, but I'm not, so I'm trying to make it electrochemically. I have 5% vinegar and lots of copper scrap, and an adjustable power supply. Unfortunately I can't barely get any current going, so I've thought of adding salt, regular NaCl. I'm curious what effect this will have on the final outcome though. Balancing equations is something I struggle with, but I'd really like to learn the chemistry here. Will the salt interfere with or alter the growth of the copper acetate crystals? Ultimately I'm trying to make calcium copper acetate crystals, I've already made the calcium acetate. To prepare copper acetate absence H2O2, employ a known method from hydrometallurgy to process copper ore employing aqueous ammonia, air (a source of oxygen) and a small amount of salt (acting as an electrolyte for this, in part, spontaneous electrochemical reaction detailed below). This results in tetra-ammine copper hydroxide. The latter exists only in solution and upon evaporation yields CuO (and possibly some Cu2O also, see this old patent). Add an acid of choice (like vinegar, a source of acetate) to convert CuO into copper acetate.
Related copper chemistry with ammonia and oxygen:
Cited half-reactions:
$\ce{1/2 O2 + H2O + 2 e- -> 2 OH-}$ (cathodic reduction of O2 at surface of the Copper)
And, at the Copper anode, the formation of the complex:
$\ce{Cu + 4 NH3 + 2 H2O -> [Cu(NH3)4(H2O)2](2+) + 2 e-}$ (anodic dissolution of Cu by a complexing agent)
With an overall reaction:
$\ce{Cu + 4 NH3 + 1/2 O2 + 3 H2O -> [Cu(NH3)4(H2O)2](2+) + 2 OH-}$
The following is multiple choice question (with options) to answer.
What substance is created when a copper turns from reddish brown to greenish brown? | [
"rust",
"copper alloy",
"iron oxide",
"copper oxide"
] | D | A: Another example of matter changing color is a penny changing from reddish brown to greenish brown as it becomes tarnished. The color change indicates that a new chemical substance has been produced. Copper on the surface of the penny has combined with oxygen in the air to produce a different substance called copper oxide. |
SciQ | SciQ-619 | zoology
Title: Why Egg shell is not called a cell wall? Egg is a single cell and has a outer hard covering outside inside which there is a cell membrane. Then why isn't the egg shell a cell wall?
Is it because no exchange of materials take place through it? Egg shells are actually porous so that the organism inside can aquire oxygen and get rid of carbon dioxide as it develops (http://www.scientificamerican.com/article/bring-science-home-chick-breathe-inside-shell/).
Although gametes (eggs and sperm) are single cells, an egg shell (or "wall" if you like) is created by the mother (therefore external to the egg cell) and contains many compartments separated by protein membranes:
https://www.exploratorium.edu/cooking/eggs/eggcomposition.html
The initial egg cell is a tiny fraction of a size of the egg visualised here, so it would therefore be incorrect to call the egg shell a "cell wall" as it is a structure independent of the egg cell itself.
The following is multiple choice question (with options) to answer.
The egg shell membrane encloses the nucleus containing the genetic material and what? | [
"cerebellum",
"exoskeleton",
"enamel",
"cytoplasm"
] | D | The ostrich egg - unfertilized, of course. Yes, this egg, just like a human ovum, is just one cell. It is a gamete with a haploid number of chromosomes, formed through meiosis. The egg shell membrane encloses the nucleus containing the genetic material and the cytoplasm. |
SciQ | SciQ-620 | thermodynamics, pressure, physical-chemistry
I think it's not valid because what is really being "added up" in Dalton's law is the effect of adding the masses of the individual gases that comprise the mixture. The partial pressure of each gas is the pressure that it would exert, for a fixed volume and temperature, if all the other gases were removed. The greater the number of gas molecules (mass) that occupy a fixed volume the greater the number of collisions per unit area of the walls of the container and thus the greater the pressure.
Thus, in my view at least, it is the extensive property of mass that is responsible for the "adding up" of the partial pressures per Dalton's Law, as opposed to pressure itself being an extensive property. We know this has to be the case because if pressure were an extensive property, the pressure a gas in a room would be cut in half if we simply divided the room in half.
Hope this helps.
The following is multiple choice question (with options) to answer.
According to dalton's law, unless they chemically react with each other, individual gases in a mixture of gases do not affect each other’s what? | [
"weight",
"density",
"pressure",
"mass"
] | C | The Pressure of a Mixture of Gases: Dalton’s Law Unless they chemically react with each other, the individual gases in a mixture of gases do not affect each other’s pressure. Each individual gas in a mixture exerts the same pressure that it would exert if it present alone in the container (Figure 9.20). The pressure exerted by each individual gas in a mixture is called its partial pressure. This observation is summarized by Dalton’s law of partial pressures: The total pressure of a mixture of ideal gases is equal to the sum of the partial pressures of the component gases: P Total = P A + P B + P C + . = Σ i P i In the equation PTotal is the total pressure of a mixture of gases, PA is the partial pressure of gas A; PB is the partial pressure of gas B; PC is the partial pressure of gas C; and so on. |
SciQ | SciQ-621 | human-biology, evolution, human-genetics
What were the last evolutionary changes in human history?
You can think of the impressive frequency of the Tay-Sachs disease in french canadian due to a bottleneck effect. Or you may think of the evolution of height, about the evolution of the shape of the skull or the evolution of feet. You can think of the reduction of our gut. etc… Your question is not well enough define so that we know if you consider the raise in frequency of Tay-Sachs disease is sufficient for you to be called a significant evolution.
Hope that helps!
The following is multiple choice question (with options) to answer.
How many mass distinctions have radically altered the history of life? | [
"six",
"five",
"one",
"four"
] | B | |
SciQ | SciQ-622 | newtonian-mechanics, forces, classical-mechanics, rotational-dynamics, statics
Under the condition that the sum of the acting forces is zero the torque is zero relative to all points if and only if it is zero relative to one point.
The proof done by computing the change of torque under a change of the basis point (so that $\vec r \mapsto \vec r' = \vec d + \vec r$):
\begin{align*}
\sum_i \vec \tau'_i &= \sum_i \vec r'_i \times \vec F_i = \sum_i (\vec r_i + \vec d) \times \vec F_i \\
&= \sum_i \vec r_i \times \vec F_i + \vec d \times \underbrace{\left(\sum_i \vec F_i\right)}_{\vec F_T} \\
&= \sum_i \vec \tau_i + \vec d \times \left( \sum_i \vec F_i \right).
\end{align*}
So the even stronger statement holds, that the sum of the torques changes by $\vec d \times \vec F_T$ under a change of reference point. If the sum of the forces acting on the body is zero, this means that the total torque does not change when the reference point is changed.
The following is multiple choice question (with options) to answer.
The vector sum of all the torques acting on an object is called what? | [
"torque load",
"net torque",
"peak capacity",
"homeostasis"
] | B | the net torque is the vector sum of all the torques acting on the object. When adding torques it is necessary to subtract CW from CCW torques. |
SciQ | SciQ-623 | inorganic-chemistry, physical-chemistry, electrochemistry, electrons, electronic-configuration
one proton's positive charge attracts one electron.
The "neutral" in a neutral atom means electrically neutral.
How can a neutral atom attract electrons when it's supposed to have zero charge ? The answer lies in electronegativity. When a proton attracts an electron, the electron doesn't magically suck out the charge of the proton. The proton's charge is still distributed in all directions. The reason why 1 proton on average can attract only 1 electron is because electrons push each other out.
Now let's first take H - it has 1 proton which attracts 1 electron. If another electron jumps in, only 1 electron stays in the end. Then He - it has 2 protons, so it attracts electrons even more. So even though electrons are fighting for the place, the nucleus charge is enough to hold them.
It gets interesting with Li. It should have 3 electrons, right? But 1st shell can take only 2 electrons, so the 3d electron must go to the 2nd shell which is further away. In such case the inner shell of electrons has a much greater effect on the outer electron, this is called electron screening, not to mention that the further you are from nucleus - the weaker the attraction. So even though Li has more protons than He, it's too weak to hold electrons on the 2nd shell, so some other atom will take the electron away and Li will be ionized and become Li$^+$ with only 2 electrons.
How strongly an atom wants new electrons is called electronegativity. It increases to the right of the periodic table because nucleus gets larger and larger and can hold on more and more electrons. In the last columns atoms want electrons so much that they can mug other atoms with weaker electronegativity.
But then the row of the table finishes and new row starts. At this point previous shell is completely filled and a new shell starts, and the electron screening kicks in again.
You can see these trends here. Electronegativity is the reason why Na & Cl can't form a molecule (covalent bond) - Cl (strong electronegativity) simply takes Na's (weak electronegativity) electron and both become ions: Cl$^-$ and Na$^+$. In the end they form an ionic bond instead.
The following is multiple choice question (with options) to answer.
What determines how strongly an atom attracts electrons to itself? | [
"enthalpy",
"gravity",
"electronegativity",
"ionization"
] | C | The electronegativity of an atom determines how strongly it attracts electrons to itself. |
SciQ | SciQ-624 | star, observational-astronomy, amateur-observing, asteroids
Title: Do objects that are invisible to the naked eye occlude much of the stars to Earth based observers? I was looking at a star recently and some other object that appeared to be stationary in relation to the star was occluding the light to only one of my eyes. This is why it caught my attention.
I was able to move my head around this shadow and see the star but there was a definite tiny area where the star was clearly hidden. The object hiding the star also appeared to be a similar size to the tiny point of light of the star. Is this common to observe?
For the last few days I have been asking myself how many objects could be hidden like this (though most with shadows that engulf the earth); How thick are asteroid belts etc, that are between our eyes and the rest of the stars.
Is most of it hidden? From your description, an object that blocks out light from a star in only one location cannot be an astronomical object.
Occultations by asteroids are fairly common. You can see a list at http://www.asteroidoccultation.com/. When a star is being occluded by an asteroid there will be a fairly narrow strip from which the star will be hidden. But it is still about 50km wide. The star appears to rapidly fade, and it remains hidden for at most a few seconds, then reappears. Your description of "only hidden to one of my eyes" doesn't fit an asteroid occultation.
The object hiding the star must, therefore, have been local, and not moving. It would be speculation to suggest what it could be.
There are may objects that are hidden in visible light, not by asteroids, but by interstellar dust clouds. We can see them by using other wavelengths.
The following is multiple choice question (with options) to answer.
Looking directly at what celestial object can cause blindness? | [
"earth",
"Moon",
"Haley's Comet",
"sun"
] | D | The Sun has many incredible surface features. Don't try to look at them, though! Looking directly at the Sun can cause blindness. Find the appropriate filters for a pair of binoculars or a telescope and enjoy!. |
SciQ | SciQ-625 | the light but not on the intensity. For more such videos please go to http://vidhyasangam.com/Videos.html Height, mass and gravitational strength. This question is off-topic. The kinetic energy is then 1 2 m i v i 2, and summation gives the total kinetic energy of the body: E kin = 1 2 m 1 v 1 2 + 1 2 m 1 v 2 2 + ⋯ = 1 2 Ω 2 ( m 1 r 1 2 + m 2 r 2 2 + ⋯ ) . Friction and movement. D. mass and velocity. Using the kinetic energy equation. Kinetic energy depends on the mass and velocity of the body in motion, with the velocity contributing more to the overall kinetic energy of the body. If you count the reduction in kinetic energy of the train together with the increase in kinetic energy of the ball, the sum is the same regardless of what reference frame you choose. Our mission is to provide a free, world-class education to anyone, anywhere. 5,000 J. solve : … Kinetic energy is one of several types of energy that an object can possess. Using the kinetic energy equation. K.E is directly proportional to temp. C. Height. Does the kinetic energy change depending on the direction of the velocity? Only velocity. B. c. D. Tags: Question 12 . $\begingroup$ @user248881 In the standard model of particle physics all photons are point particles, i,e, have no size. It is given as K E = a s 2, where a is a constant. kinetic energy synonyms, kinetic energy pronunciation, kinetic energy translation, English dictionary definition of kinetic energy. The kinetic energy of a moving object can be calculated using the equation: Kinetic energy = $$\frac{1}{2}$$ x mass x (speed) 2. 2 See answers Nonportrit Nonportrit The amount of kinetic energy an object has depends on its "speed." Only mass. You are very important to us. Linear Kinetic energy of a object is dependent upon the linear speed of an object and its mass( we can use the scalar term “speed” as energy is a scalar quantity and is independent of the direction of motion of body). Kinetic energy depends on A. only mass. When the particles are moving very fast, we feel the substance and say "That's hot!". The equation
The following is multiple choice question (with options) to answer.
The amount of kinetic energy in a moving object depends directly on what two factors? | [
"gravity and weight",
"mass and velocity",
"inertia and momentum",
"revolution and velocity"
] | B | The amount of kinetic energy in a moving object depends directly on its mass and velocity. It can be calculated with the equation: . |
SciQ | SciQ-626 | ## Ch112
The aorta carries blood away from the heart at a speed of about 39 cm/s and has a radius of approximately 1.0 cm. The aorta branches eventually into a large number of tiny capillaries that distribute the blood to the various body organs. In a capillary, the blood speed is approximately 0.072 cm/s, and the radius is about 6.2 x 10-4 cm. Treat the blood as an incompressible fluid, and use these data to determine the approximate number of capillaries in the human body.
• solve in the same approach...
The aorta carries blood away from the heart at a speed of about 44 cm/s and has a radius of approximately 1.2 cm. The aorta branches eventually into a large number of tiny capillaries that distribute the blood to the various body organs. In a capillary, the blood speed is approximately 0.071 cm/s, and the radius is about 6.4 x 10-4 cm. Treat the blood as an incompressible fluid, and use these data to determine the approximate number of capillaries in the human body.
Solution:
The volume has to be the same, so:
44cm/s * 1.44pi cm^2 = 199.05 cm^3/s
so x(.071cm/s * pi*.00064^2) = 199.05cm^3/s
x = (44 * 1.44pi)/(.071 * pi * .00064^2) = 2.17869718 * 10^9 capillaries
• The aorta carries blood away from the heart at a speed of about 37 cm/s and has a radius of approximately 1.2 cm. The aorta branches eventually into a large number of tiny capillaries that distribute the blood to the various body organs. In a capillary, the blood speed is approximately 0.069 cm/s, and the radius is about 6.3 x 10^-4 cm. Treat the blood as an incompressible fluid, and use these data to determine the approximate number of capillaries in the human body.
Flow rate = Cross sectional area * speed
Blood flow from the aorta = (pi)(1.2)^2(37) = 167.38 cm^3/sec.
The following is multiple choice question (with options) to answer.
What is the movement of fluid out of the capillaries called? | [
"diffusion",
"osmosis",
"absorption",
"filtration"
] | D | 20.3 Capillary Exchange Small molecules can cross into and out of capillaries via simple or facilitated diffusion. Some large molecules can cross in vesicles or through clefts, fenestrations, or gaps between cells in capillary walls. However, the bulk flow of capillary and tissue fluid occurs via filtration and reabsorption. Filtration, the movement of fluid out of the capillaries, is driven by the CHP. Reabsorption, the influx of tissue fluid into the capillaries, is driven by the BCOP. Filtration predominates in the arterial end of the capillary; in the middle section, the opposing pressures are virtually identical so there is no net exchange,. |
SciQ | SciQ-627 | human-biology, cancer, medicine
Title: Why are only few cigarette smokers prone to cancer? It's tacit that only a few populace of smokers get cancer. What spares the others from it or what specifically cause cancer in those populace? See this Washington Post Article Cigarette smokers are most certainly prone to cancer. See Cecil Medicine, Chapter 183, on the epidemiology of cancer, exposure to tobacco is the most important environmental risk factor for cancer development, at least in the US:
Exposure to tobacco is the single largest cause of cancer in the United States... All forms of tobacco can cause cancer. Cigarette smoking causes cancer of the lip, oral cavity, nasal cavity, paranasal sinuses, pharynx (nasal, oral, and hypopharnyx), larynx, lung, esophagus (squamous cell and adenocarcinoma), stomach, colorectum, pancreas, liver, kidney (adenocarcinoma and renal pelvis), urinary bladder, uterine cervix, and myeloid leukemia.
Cancer may be identified or the cause of death in fewer smokers than might be expected, though, because smoking is an even greater risk factor for cardiovascular disease, and death due to cardiovascular disease.
Cancer is an unlikely phenomenon in an individual cell, but becomes more likely at the organism level, and even more likely over time. Though tobacco may be the most important environmental risk factor for cancer, age is actually a stronger predictor of cancer (see again, Cecil Chapter 183. Autopsy studies give us a quite remarkable example, this one shows incidental prostate cancer in nearly 60% of men over 80 who died from other causes. That figure is not out of the ordinary. Live long enough and you are likely to develop cancer.
Death due to heart disease may account for the lower than expected rates of cancer diagnoses and deaths in smokers. Nothing prevents cancer as well as dying from something else. And as discussed in the blog in the Washington Post you linked to, up to 2/3 of smokers die from smoking related causes
The following is multiple choice question (with options) to answer.
The prevalence of cervical cancer in the united states is very low because of regular screening exams called what? | [
"prostates exams",
"mammograms",
"pap smears",
"Stavros smears"
] | C | The prevalence of cervical cancer in the United States is very low because of regular screening exams called pap smears. Pap smears sample cells of the cervix, allowing the detection of abnormal cells. If pre-cancerous cells are detected, there are several highly effective techniques that are currently in use to remove them before they pose a danger. However, women in developing countries often do not have access to regular pap smears. As a result, these women account for as many as 80 percent of the cases of cervical cancer worldwide. In 2006, the first vaccine against the high-risk types of HPV was approved. There are now two HPV vaccines available: Gardasil® and Cervarix®. Whereas these vaccines were initially only targeted for women, because HPV is sexually transmitted, both men and women require vaccination for this approach to achieve its maximum efficacy. A recent study suggests that the HPV vaccine has cut the rates of HPV infection by the four targeted strains at least in half. Unfortunately, the high cost of manufacturing the vaccine is currently limiting access to many women worldwide. |
SciQ | SciQ-628 | aqueous-solution, solubility
Title: Definition of "soluble" How to define "soluble" in chemistry?
For example, in 1:1 v/v, benzene does not mix with water, i.e. insoluble. Common sense.
However, in an analytical procedure, it called for making a "saturated" aqueous solution of benzene, which is about 1.5 g/L. So, benzene actually has some solubility in water.
So, my question is, is there an official definition of "soluble"? We consider if a solute is completely spread out through the solvent in the maximum possible extent, we consider the solute to be dissolved in the solvent. We can identify a solution by a few characteristics:
Solutions are uniform and have no precipitation or coagulated mass in it.
Solutions are clear, no granules or anything.
Solutions exhibit the phase of the solvent.
The following is multiple choice question (with options) to answer.
There is a predictable amount of solute that can be dissolved at what? | [
"specific temperature",
"room temperature",
"flat rate",
"light speed"
] | A | There is a predictable amount of solute that can be dissolved at a specific temperature. |
SciQ | SciQ-629 | cell-biology, nutrition, blood-circulation, liver
Title: How do nutrients get to the cells they need to get to? I understand the basics of digestion. I know that nutrients get absorbed by the microvilli, enter the bloodstream and travel to the liver but after all that, what is the biological mechanism that guides these nutrients to the proper receiving location? Broadly speaking, nutrients that enter the blood from the gut, and those that are released into the blood by the liver, are available to any cells that require them. So there is no "guiding to the correct location" in the sense that you suggest.
Lipids for example are present in the various lipoproteins and can be acquired from these by all cells. Iron is bound to transferrin, and any cell with transferrin receptors can internalise the transferrin and take the iron. Glucose is available in solution in the plasma, and free fatty acids are bound to serum albumin in the blood. During starvation the liver produces ketones ("ketone bodies") which are taken up by many different tissues/cell types.
The following is multiple choice question (with options) to answer.
Carrier proteins bind and carry the molecules across what cell structure? | [
"nucleus",
"plastid",
"cell membrane",
"cell wall"
] | C | Carrier proteins bind and carry the molecules across the cell membrane. These proteins bind a molecule on one side of the membrane, change shape as they carry the molecule across the membrane, and deposit the molecule on the other side of the membrane. Even though a protein is involved in both these methods of transport, neither method requires energy. Therefore these are still types of passive transport. |
SciQ | SciQ-630 | geology, geomorphology, coastal
Title: What causes such a narrow slit in a cliff? (see photo)
I have this photo as a background image and I often wonder how such a narrow, well-defined slit could be formed. Is it natural or man-made? If natural, what processes could have formed it? The rest of the coastline is rugged but this appears very uniform. It is on the north-west coast of Jersey (UK). If you see the other user (Jan Doggen's) google maps link, you can see apparently similar features in different states - this is a particularly neat example of a general phenomenon.
These notches form when headlands are undercut by caves carved out by the sea. They may be initiated where there is a fault or jointing in the rock (northwest Jersey is granite, according to google).
In this particular case, the notch seems to have a rounded termination. Blowholes also form from undercutting of headlands producing caves whose roofs then collapse. It's possible this cave may have collapsed after a blowhole formed, so you get a notch where the inland end of the feature appears rounded. That bit is just speculation though.
I found this Jersey geology trail guide that might have more detail: http://jerseygeologytrail.net/Geomorph.shtml
The following is multiple choice question (with options) to answer.
As per hutton's unconformity, what happened to the intermediate layers of rock? | [
"they eroded away",
"they metamorphized",
"they expanded",
"they fused"
] | A | Look at the rock layers pictured below ( Figure below ); they show a feature called Hutton’s unconformity. The unconformity was discovered by James Hutton in the 1700s. Hutton saw that the lower rock layers are very old. The upper layers are much younger. There are no layers in between the ancient and recent layers. Hutton thought that the intermediate rock layers eroded away before the more recent rock layers were deposited. |
SciQ | SciQ-631 | terminology, meteorology
I've tried to illustrate the relationships with insolation and temperature here:
There are some other ways too:
Ecological. Scientists who study the behaviour of organisms (hibernation, blooming, etc.) adapt to the local climate, sometimes using 6 seasons in temperature zones, or only 2 in polar and tropical ones.
Agricultural. This would centre around the growing season and therefore, in North America and Europe at least, around frost.
Cultural. What people think of as 'summer', and what they do outdoors (say), generally seems to line up with local weather patterns. In my own experience, there's no need for these seasons to even be 3 month long; When I lived in Calgary, summer was July and August (hiking), and winter was December to March (skiing). Here's another example of a 6-season system, and a 3-season system, from the Aboriginal people of Australia, all based on weather.
Why do systems with later season starting dates prevail today? Perhaps because at mid-latitudes, the seasonal lag means that the start of seasonal weather is weeks later than the start of the 'insolation' period. In a system with no heat capacity, there would be no lag. In systems with high heat capacity, like the marine environment, the lag may be several months (Ibid.). Here's what the lag looks like in three mid-latitude cities:
The exact same effect happens on a diurnal (daily) basis too — the warmest part of the day is often not midday (or 1 pm in summer). As with the seasons, there are lots of other factors too, but the principle is the same.
These aren't mutually exclusive ways of looking at it — there's clearly lots of overlap here. Cultural notions of season are surely rooted in astronomy, weather, and agriculture.
The following is multiple choice question (with options) to answer.
What kind of summers do humid continental climates have? | [
"dry summers",
"wet summers",
"cold summers",
"warm summers"
] | C | Humid continental climates have warm winters and cold summers. Subarctic climates have cool short summers and very cold winters. |
SciQ | SciQ-632 | thermodynamics
[...] can we say that water holds the heat more than other liquids
Compared to other substances (or mixtures of substances) with a lower specific heat capacity, yes.
On request of the OP:
Specific heat capacity is the amount of heat energy needed to heat $1\text{ }\mathrm{kg}$ of the material by one $1\text{ }\mathrm{K}$:
$$c_p(T)=\frac{1}{m}\Big(\frac{\text{d}Q}{\text{d}T}\Big)_T$$
If $c_p$ is constant over an interval $\Delta T$, then we can write:
$$c_p=\frac{\Delta Q}{m\Delta T}$$
For a uniform object made of a material of specific heat capacity $c_p$ and of mass $m$ its heat capacity is:
$$C=mc_p$$
The following is multiple choice question (with options) to answer.
Compared to others, what type of liquid has a relatively high surface tension and heat capacity? | [
"wine",
"water",
"oil",
"blood"
] | B | Compared to other liquids, water has a relatively high surface tension and heat capacity. Both of these properties are partially a result of the strong hydrogen bonds that hold water molecules together. |
SciQ | SciQ-633 | bacteriology
Saier, MH. & Bogdanov, V. (2013) Membranous Organelles in Bacteria. JOURNAL OF MOLECULAR MICROBIOLOGY AND BIOTECHNOLOGY 23: 5-12 DOI: 10.1159/000346496
Free full text here.
The language used in this review seems to support the existence of mesosomes as some sort of intermediate in the formation of intracellular membranes in prokaryotes. This review is a polemic in favour of the idea that prokaryotes do indeed contain intracellular membrane-bounded compartments. It has no abstract, but the first paragraph gives a flavour of its stance:
The traditional view of life on Earth divides the living world into two major groups, prokaryotes and eukaryotes. These two groups were originally suggested to differ in very basic respects. While eukaryotes had complex cell structures including a cytoskeleton and intracellular membrane-bounded organelles, prokaryotes were believed to lack them. In fact, numerous textbooks and current sources still note this distinction and hold it to be true. For example, in Campbell’s Biology [Campbell, 1993, p. 515] it is stated without equivocation: ‘Prokaryotic cells lack membrane-enclosed organelles.’ In ‘Functional Anatomy of Prokaryotic and Eukaryotic Cells’ [Tortora et al., 2009, chapt. 4] it is similarly claimed that ‘Prokaryotes lack membrane-enclosed organelles, specialized structures that carry on various activities’. In the current Wikipedia, under ‘Prokaryote’ the following statement can be found: ‘The prokaryotes are a group of organisms whose cells lack a cell nucleus (karyon) or any other membrane-bounded organelles’. In the same online compendium under ‘Organelle’, one can read: ‘whilst prokaryotes do not possess organelles per se, some do contain protein-based microcompartments’. Proteinceous microcompartments will be the subject of a forthcoming Journal of Molecular Microbiology and Biotechnology written symposium, but this one will show that these generalizations, suggesting a lack of subcellular compartmentalization in prokaryotes, are blatantly in error [Murat et al., 2010a].
The following is multiple choice question (with options) to answer.
Cilia and flagella are extensions of what? | [
"cell wall",
"cell nucleus",
"plasma membrane",
"protoplasm"
] | C | Cilia and flagella are extensions of the plasma membrane. |
SciQ | SciQ-634 | everyday-chemistry, metal, toxicity
*Spin-off questions:
Is there any substance to my teacher's claim? How come those asses that performed this mundane task survived and now live (seemingly) normal lives without going insane? Were they already insane prior to touching the mercury? Should I just go and touch some mercury, partly to discover if it is indeed possible to touch metal mercury safely (and partly just to let out all the stress that built up while typing out this question)? Mercury is toxic, but you need to carefully define what you mean by toxic or you draw incorrect conclusions
Toxic is a broad term. It means a lot of different things. The timescale matters. Some toxic things take years to exhibit their effects; others act instantly.
A binary distinction between toxic and not-toxic is pretty meaningless: you need to define the context and the timescale of the toxicity.
Mercury metal and mercury compounds are usually considered toxic. But their effects are varied in time and degree. Mercury metal is pernicious but only if you are exposed to it over a long time period. In fact you could probably drink it with few ill effects. The body just doesn't absorb it quickly. What is dangerous about mercury is not short term exposure to the metal but long term exposure to the vapour. This is why people don't suffer immediate ill effects when handling the metal even without skin protection.
Mercury vapour is readily absorbed in the body and will accumulate in tissue causing a variety of long term effects. This was discovered by mercury miners who often developed long term problems from their exposure. And it was documented for science by some chemists who started to suffer effects after working with the metal over long periods of time and managed to document their own decline (see Stock's work, for example). Mercury metal is often widely used in laboratories to provide a limited overpressure for gas distribution (you allow the gas to bubble through a mercury manometer).
Since the toxicity was recognised, chemists have been a lot more careful and always avoid vapour buildup by working in well ventilated spaces and making sure that manometers containing mercury are vented safely to the outside (via scrubbing filters) along with other potentially toxic vapours.
There is little immediate risk when working with metallic mercury as long as you don't spill it somewhere where it will collect and allow vapour to build up in the atmosphere.
The following is multiple choice question (with options) to answer.
Mercury and lead, which was once widely used in paint and gasoline, are examples of what type of metals? | [
"gaseous heavy metals",
"toxic heavy metals",
"sulfuric heavy metals",
"alloys"
] | B | Toxic heavy metals include mercury and lead. Mercury is used in some industrial processes. It is also found in fluorescent light bulbs. Lead was once widely used in gasoline, paint, and pipes. It is still found in some products. |
SciQ | SciQ-635 | cell-division
Title: Are free-nuclear division and endomitosis the same? As far as I understood it, both are cases of karyokinesis, not followed by cytokinesis. No. If you google the terms you'll get a lot of sites with definitions. For example:
Nuclear division
Definition
noun
The process by which a nucleus divides, resulting in the segregation of the genome to opposite poles of a dividing cell.
source: http://www.biology-online.org/dictionary/Nuclear_division
Edit:
or
free nuclear division mitotic division of nuclei without accompanying cytokinesis, i.e. nuclei divide in a common cytoplasm, the cells walls only forming around each later
source: http://ecflora.cavehill.uwi.edu/bio_courses/bl14apl/Gloss.htm
versus
endomitosis
mitosis taking place without dissolution of the nuclear membrane, and not followed by cytoplasmic division, resulting in doubling of the number of chromosomes within the nucleus.
source: http://medical-dictionary.thefreedictionary.com/endomitosis
or a bit more revealing:
Duplicated chromosomes produced by endomitosis exist as discrete units
in a single polyploid nucleus or may be packaged into separate nuclei,
depending on the phase at which mitosis is aborted
source: http://en.wikipedia.org/wiki/Endoreduplication
So as you see by definition nuclear division is part of a bigger process (cell division), and accoriding to the first source karyokinesis is a synonim for nuclear division (karyo = nucleus kinesis = moving, both come form greek language).
Edit:
If you check the definition above, you can see that free-nuclear division is a mitosis without cytokinesis, thus chromosome separation still occurs.
In endomitosis the can end up with a polyploid nucleus, in contrast to the other two aforementioned mechanism where no polyploidy occurs.
The following is multiple choice question (with options) to answer.
During karyogamy, the haploid nuclei contributed by the two parents fuse, which produces what? | [
"arisen cells",
"cancer cells",
"mutated cells",
"diploid cells"
] | D | |
SciQ | SciQ-636 | polymers, plastics
Title: What is Polymer Environmental Resin (PER)? I'm no chemist and I probably wouldn't understand any technical answer but...
I'm investigating the environmental impacts of various materials as compared to PVC and this is one that crops up regularly as a more environmental alternative.
Unfortunately there does not seem to be any authoritative information on the web concerning this material.
I'm beginning to think that this is a green-washing propaganda move by the phthalate/heavy metal free PVC industry as a move avoid mentioning PVC in product advertising.
Anyway I would welcome any information on what exactly PER is and what it is made from.
Thank you. PER is essentially PVC which has been plasticized and stabilized with acetyl tributyl citrate, instead of the host of phthalate-based plasticizers such as bis-diethylhexyl phthalate (DEHP) whose endocrine-disrupting properties give PVC its well-deserved bad reputation.
Citrate salts tend to be readily water soluble, and therefore this material is touted to be more biodegradeable than phthalate-plasticized PVC. I certainly cannot find any information to refute that claim. ATBC will further degrade into other acetates and butyrates, most of which are relatively common and harmless in the environment (though butyl compounds are infamously stinky; butyric acid is a favorite less-lethal offensive-odor weapon of law enforcement and groups like the Sea Shepherds). All PVC will eventually degrade as the plasticizer leaches out over time, unlike other types of plastics that are so ridiculously inert they'll likely be the fossils of our modern era, but again, the phthalates just aren't a great idea to have in the environment.
The following is multiple choice question (with options) to answer.
What is polyisoprene better known as? | [
"styrofoam",
"rayon",
"silicon",
"rubber"
] | D | Polyisoprene is a polymer of isoprene and is better known as rubber. It is produced naturally by rubber trees, but several variants have been developed which demonstrate improvements on the properties of natural rubber. |
SciQ | SciQ-637 | physical-chemistry, equilibrium, kinetics, stoichiometry
I might try to give you some intuition to back up that, for a given (elementary) reaction $\ce{A ->[k] B}$, the reaction rate $r$ can be written as
$$r = \frac{d P_\ce{B}}{dt} = -\frac{d P_\ce{A}}{dt} \propto P_\ce{A}\text{.}$$
(Observe that the second equality above is true due to $P_\ce{A} + P_\ce{B} = \text{constant}$.)
First, for an ideal gas, $P_\ce{A} = \frac{n_\ce{A}}{V} RT$.
This means that $P_\ce{A} \propto n$ for fixed temperature and volume.
Let's say the reaction happens as a random process.
That is to say that, for every time interval $\Delta t$, we have a probability per unit time $p$ of having a single molecule $\ce{A}$ turning into $\ce{B}$.
If we wait longer, proportionally more molecules will turn.
We'll thus have, for initially $n_\ce{A}$ molecules of $\ce{A}$, after $\Delta t$ seconds,
$$\Delta n_\ce{B} = p n_\ce{A} \Delta t\text{.}$$
This means that, in the time interval $\Delta t$, the population of $\ce{B}$ goes from 0 to $\Delta n_\ce{B}$ (assuming no $\ce{B}$ initially).
From the stoichiometry of the reaction, $\Delta n_\ce{B} = -\Delta n_\ce{A}$ (i.e., there's conservation of moles).
Thus,
$$\frac{\Delta n_\ce{B}}{\Delta t} = -\frac{\Delta n_\ce{A}}{\Delta t} = p n_\ce{A}\text{.}$$
The following is multiple choice question (with options) to answer.
Every chemical reaction occurs with a concurrent change in what? | [
"energy",
"mass",
"neutrons",
"hydrogen"
] | A | Every chemical reaction occurs with a concurrent change in energy. |
SciQ | SciQ-638 | cell-biology, nutrition, blood-circulation, liver
Title: How do nutrients get to the cells they need to get to? I understand the basics of digestion. I know that nutrients get absorbed by the microvilli, enter the bloodstream and travel to the liver but after all that, what is the biological mechanism that guides these nutrients to the proper receiving location? Broadly speaking, nutrients that enter the blood from the gut, and those that are released into the blood by the liver, are available to any cells that require them. So there is no "guiding to the correct location" in the sense that you suggest.
Lipids for example are present in the various lipoproteins and can be acquired from these by all cells. Iron is bound to transferrin, and any cell with transferrin receptors can internalise the transferrin and take the iron. Glucose is available in solution in the plasma, and free fatty acids are bound to serum albumin in the blood. During starvation the liver produces ketones ("ketone bodies") which are taken up by many different tissues/cell types.
The following is multiple choice question (with options) to answer.
What receives blood in the heart? | [
"the epidermis",
"the atria",
"ventricle",
"chamber"
] | B | The atria receive blood and the ventricles pump blood out of the heart. |
SciQ | SciQ-639 | organic-chemistry, biochemistry, home-experiment, mixtures, colloids
The strong acid conditions that arise from adding $\ce{H2SO4}$ will protonate these head groups, neutralizing the negative charge and vastly weakening their emulsifying properties.
Triglycerides. Triglycerides are the molecules that provide most of the fat content of milk. They are triacylglycerols. Unlike phospholipids, they have no polar head groups, and thus they do not dissolve in water. They would "want" to form a separate, oily phase from the water (just like mixing vegetable oil and water), but the fact that they are usually bound in tiny droplets by phospholipids prevents this separation. Because triglyceride oils are less dense than water, if they did ever get the chance to coalesce into large droplets, they would rise to the top of the milk. This happens when cream naturally separates from fresh (raw) milk, but in homogenized milk, the droplets are artificially forced to much smaller sizes, effectively preventing the droplets from coalescing or rising.
Upond acidification, the loss of phospolipid surfactant activity breaks down the stability of the fatty droplets, allowing them to rapidly coalesce, so they rise to the top of the tube, a process that is only accelerated by centrifugation.
Hydrolysis of triglycerides in the acid is possible, but unlikely. In addition to required prolonged incubation or high temperatures, keep in mind that the separated triglyceride phase is actually not exposed to the acidic solution very much at all.
The following is multiple choice question (with options) to answer.
Fatty acids, triglycerides, phospholipids, and steroids are examples of what? | [
"tissues",
"enzymes",
"proteins",
"lipids"
] | D | Lipids are a diverse class of relatively nonpolar biomolecules that generally do not dissolve well in water. Common types of lipids include fatty acids, triglycerides, phospholipids, and steroids. |
SciQ | SciQ-640 | photosynthesis, chloroplasts
Title: Chloroplasts in an animal cell What would happen if we inject a chloroplast organelle into an animal cell?
Will the animal cell destroy it? Or is it possible that the chloroplast will somehow survive, and even replicate? Could there be photosynthesis in such a cell, or will some of the necessary mechanisms be missing? To answer your bigger question:
Yes, most of this is possible - under some conditions -, and animals and animal cells can acquire chloroplasts, and use them.
E.g.: see Elysia chlorotica whose cells actively take up chloroplasts and use them, and keep them alive (though not replicating). - Though some genes of algae are also contained in the Elysia chlorotica genome - which may be considered as partial replication.
Also there are salamanders that have replicating algae within them (since embryogenesis) - even algae (with chloroplasts) within animal cells - though here the algae might be rather understood as symbionts or "cell types", and the animal cells don't have the chloroplasts by themselves.
The following is multiple choice question (with options) to answer.
Where in the cell does photosynthesis occur? | [
"cell wall",
"pathogen",
"chloroplast",
"genome"
] | C | Photosynthesis occurs in the chloroplast of the plant cell. |
SciQ | SciQ-641 | human-biology, neuroscience, physiology, anatomy
Title: Why does sympathetic activity constrict pulmonary vessels? I don't know understand why sympathetic stimulation constricts pulmonary vessels?
I thought that the sympathetic nervous system activated the body for physical activity. Physical activity would need more oxygen supply. Doesn't constriction of pulmonary vessels reduce the gas exchange? Short answer
The sympathetic nervous system mediates the fight, flight and fright response. It constricts the arteries and arterioles to increase blood pressure, in turn pushing the blood to the muscles and other organs vital for physical activity.
Background
The sympathetic nervous system functions triggers the fight, fright, flight (FFF) response (Fig. 1). It provides the body with a burst of energy so that it can respond to danger (source: Harvard Medical School).
The FFF response is initiated in the hypothalamus by activating the sympathetic nervous system through the adrenal glands. These glands release epinephrine (adrenaline) into the bloodstream. Epi increases heart rate and blood pressure to push blood to the muscles, heart, and other vital organs. The person also starts to breathe more rapidly and the small airways in the lungs open up. This way, the lungs can take in as much oxygen as possible with each breath. Extra oxygen is sent to the brain, increasing alertness (source: Harvard Medical School).
In blood vessels, as you say, sympathetic activation constricts arteries and arterioles (resistance vessels), which increases vascular resistance and decreases distal blood flow. When this occurs throughout the body, the increased vascular resistance causes arterial pressure to increase (Klabunde, 2012). This enhances the distribution of oxygen already present in the blood. I don't think the pulmonary circulation responds differently than that in the rest of the body. The stress response is meant to support the evasion of acute dangers. But indeed, chronic exposure to adrenaline may eventually lead to impaired oxygen exchange in the lungs (Krishnamoorthy et al., 2012).
Fig. 1. Fight, flight, fright response. source: Freelap USA
References
- Klabunde, Cardiovascular Physiology Concepts, 2nd ed. (2012). Lippincott Williams & Wilkins
- Krishnamoorthy et al., Anesthesiology (2012); 117(10): 745-54
The following is multiple choice question (with options) to answer.
Sympathetic stimulation also triggers the release of epinephrine and norepinephrine, which enhance both cardiac output and what else? | [
"vasoconstriction",
"inhibition",
"vasodilation",
"digestion"
] | A | pressure and maintaining blood flow. Ultimately, however, blood volume will need to be restored, either through physiological processes or through medical intervention. In response to blood loss, stimuli from the baroreceptors trigger the cardiovascular centers to stimulate sympathetic responses to increase cardiac output and vasoconstriction. This typically prompts the heart rate to increase to about 180–200 contractions per minute, restoring cardiac output to normal levels. Vasoconstriction of the arterioles increases vascular resistance, whereas constriction of the veins increases venous return to the heart. Both of these steps will help increase blood pressure. Sympathetic stimulation also triggers the release of epinephrine and norepinephrine, which enhance both cardiac output and vasoconstriction. If blood loss were less than 20 percent of total blood volume, these responses together would usually return blood pressure to normal and redirect the remaining blood to the tissues. Additional endocrine involvement is necessary, however, to restore the lost blood volume. The angiotensin-reninaldosterone mechanism stimulates the thirst center in the hypothalamus, which increases fluid consumption to help restore the lost blood. More importantly, it increases renal reabsorption of sodium and water, reducing water loss in urine output. The kidneys also increase the production of EPO, stimulating the formation of erythrocytes that not only deliver oxygen to the tissues but also increase overall blood volume. Figure 20.21 summarizes the responses to loss of blood volume. |
SciQ | SciQ-642 | species-identification, entomology
Title: Can you identify this animal?
It was in the bathroom, 2cm in lenght (or so). It has two small antenas on the head. I live on Balkan peninsula, inland. That is a European Millipede.
I found this picture by searching European Millipede. Obviously there are different types - and this is the one you have.
Here is a wiki link I found: https://en.wikipedia.org/wiki/Cylindroiulus
I think your specifically is a Cylindroiulus britannicus
.
The following is multiple choice question (with options) to answer.
Not surprisingly, centipedes, millipedes and other members of the subphylum myriapoda are adapted to living on what? | [
"tree",
"land",
"sand",
"water"
] | B | Centipedes and millipedes belong to the subphylum Myriapoda, which contains 13,000 species. They all live on land, which makes sense as all those legs are more adapted to a terrestrial lifestyle, as opposed to an aquatic lifestyle. |
SciQ | SciQ-643 | ecology
Title: Statement about Tropical Rainforests I made a statement about tropical rainforests, and I want to know if it's somewhat true or not:
The soil in tropical rainforests is not exceptionally fertile, because it contains few minerals. The reason that a tropical rainforest has a huge amount of vegetation is because of the quick mineralisation. If a dead leaf falls onto the ground, it immediately gets turned into minerals, which the plants immediately use for sustaining theirselves There are many websites which describe this phenomenon. They all seem to confirm the basic premise of the question: in tropical rain forests most of the minerals are held in the biomass and rapid decomposition contributes to the recycling of these nutrients for new growth. One example is here.
Tropical rainforests are noted for the rapid nutrient cycling that occurs on the ground. In the tropics, leaves fall and decompose rapidly. The roots of the trees are on the surface of the soil, and form a thick mat which absorbs the nutrients before they reach the soil (or before the rain can carry them away). The presence of roots on the surface is a common phenomenon in all mature forests; trees that come along later in succession win out in competition for nutrients by placing their roots over top of the competitors, and this pattern is seen in the temperate rainforest as well. What does not occur in the temperate rainforest, however, is a rapid cycling of nutrients. Because of the cold conditions and the acidity released by decomposing coniferous needles on the forest floor, decomposition is much slower. More of the nutrients are found in the soil here than would be the case in a tropical forest, although like the tropical forest most of the nutrients are held in the plants and animals themselves.
I looked for actual evidence of these differences in rates of decomposition and I found this:
Salinas, N. et al. (2011) The sensitivity of tropical leaf litter decomposition to temperature: results from a large-scale leaf translocation experiment along an elevation gradient in Peruvian forests. New Phytologist 189: 967-977
The following is multiple choice question (with options) to answer.
What are found in moist forests that break down decaying plant material? | [
"spirogyra",
"trichina",
"myriapoda",
"organism"
] | C | Myriapoda are usually found in moist forests, where they break down decaying plant material. |
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