questions stringlengths 37 1.22k | reasoning stringlengths 0 3.56k ⌀ | answers stringlengths 4 138 |
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Where does fertilization usually take place?
Here are the choices:
A. ovary
B. uterus
C. vagina
D. fallopian tubes | A day or two after an ovary releases an egg, the egg may unite with a sperm. Sperm are deposited in the vagina during sexual intercourse. They propel themselves through the uterus and enter a fallopian tube . This is where fertilization usually takes place. | D: fallopian tubes. |
What monitors the level of carbon dioxide in the blood?
Here are the choices:
A. the brain stem
B. the lungs
C. the heart
D. the kidneys | The regular, rhythmic contractions of the diaphragm are controlled by the brain stem. It sends nerve impulses to the diaphragm through the autonomic nervous system. The brain stem monitors the level of carbon dioxide in the blood. If the level becomes too high, it “tells” the diaphragm to contract more often. Breathing speeds up, and the excess carbon dioxide is released into the air. The opposite events occur when the level of carbon dioxide in the blood becomes too low. In this way, breathing keeps blood pH within a narrow range. | A: the brain stem. |
When volume does not change, temperature is proportional to what other property?
Here are the choices:
A. pressure
B. resistance
C. Density
D. Length | Pressure and temperature at constant volume are directly proportional. | A: pressure. |
Single-displacement reactions are a subset of what?
Here are the choices:
A. gravitational reactions
B. redox reactions
C. particle reactions
D. kinetic reactions | Single-displacement reactions are a subset of redox reactions. In this subset, what is oxidized and what is reduced? Give an example of a redox reaction that is not a single-displacement reaction. | B: redox reactions. |
What is the process by which the substances you consume are taken up by the blood?
Here are the choices:
A. digestion
B. evaporation
C. filtration
D. absorption | Absorption is the process that allows substances you eat to be taken up by the blood. After food is broken down into small nutrient molecules, the molecules are absorbed by the blood. After absorption, the nutrient molecules travel in the bloodstream to cells throughout the body. This happens mostly in the small intestine. | D: absorption. |
Why do electronegativities decrease from top to bottom?
Here are the choices:
A. larger atomic variation
B. larger atomic size
C. larger electric pull
D. smaller atomic size | Electronegativities generally increase from left to right across a period. This is due to an increase in nuclear charge because of the greater number of protons in the nucleus. Alkali metals have the lowest electronegativities, while halogens have the highest. Because most noble gases do not form compounds, they are generally not assigned electronegativity values. Note that there is little variation among the transition metals. Electronegativities generally decrease from top to bottom within a group due to the larger atomic size. | B: larger atomic size. |
What are the three types of symbiosis?
Here are the choices:
A. internalization , parasitism , commensalism
B. commensalism, osmosis, internalization
C. connectionism , parasitism , commensalism
D. mutualism, parasitism, commensalism | Symbiosis is a close relationship between two species in which at least one species benefits. For the other species, the relationship may be beneficial, harmful, or neutral. There are three types of symbiosis: mutualism, parasitism, and commensalism. | D: mutualism, parasitism, commensalism. |
What term is used to describe the ability to change or move matter?
Here are the choices:
A. mass
B. energy
C. speed
D. inertia | Everything you do takes energy. Energy is the ability to change or move matter. Whether it’s reading these words or running a sprint, it requires energy. In fact, it takes energy just to stay alive. Where do you get energy? You probably know the answer. You get energy from food. Figure {{ref|MS-LS-SE-02-03-Food|below}] shows some healthy foods that can provide you with energy. | B: energy. |
What measures exactly how much gravity is pulling on something?
Here are the choices:
A. weight
B. dimension
C. matter
D. size | The amount of inertia an object has is simply related to the mass of the object. Mass and Weight are two different things. Mass (typically in units of kg or grams) is basically a measure of what comprises an object. Weight is the measure of how much the force of gravity is pulling on you. In fact, instead of saying 'I weigh 80 lb. ', one could say that 'the force of gravity is pulling on me with a force of 80 lb. ' The metric unit for weight (and force) is the Newton. | A: weight. |
Where do producers in an ecosystem generally get their energy from?
Here are the choices:
A. predators
B. consumers
C. chlorophyll
D. the sun | The survival of every ecosystem is dependent on the producers. Without producers capturing the energy from the sun and turning it into glucose, an ecosystem could not exist. On land, plants are the dominant producers. Phytoplankton , tiny photosynthetic organisms, are the most common producers in the oceans and lakes. Algae, which is the green layer you might see floating on a pond, are an example of phytoplankton. | D: the sun. |
Generators usually transform kinetic energy into what kind of energy?
Here are the choices:
A. potential energy
B. electrical energy
C. subsequent energy
D. nuclear energy | Generators may produce either alternating or direct current, but they all change kinetic energy to electrical energy. | B: electrical energy. |
Most modern seed plants are angiosperms that produce seeds in the what of flowers?
Here are the choices:
A. stems
B. ovaries
C. kidneys
D. lungs | Most modern seed plants are angiosperms that produce seeds in the ovaries of flowers. | B: ovaries. |
Most enzymes are classified as what?
Here are the choices:
A. hormones
B. proteins
C. lipids
D. acids | B: proteins. | |
Each hemisphere of the brain contains regions called what that are involved in different functions?
Here are the choices:
A. lobes
B. nodes
C. chambers
D. folds | Visit the following website (http://openstaxcollege. org/l/split-brain2) to learn more about split-brain patients and to play a game where you can model split-brain experiments yourself. Each hemisphere contains regions called lobes that are involved in different functions. Each hemisphere of the mammalian cerebral cortex can be broken down into four functionally and spatially defined lobes: frontal, parietal, temporal, and occipital (Figure 16.22). | A: lobes. |
Emphysema is a chronic disease caused by the breakdown of the what tissue?
Here are the choices:
A. liver
B. brain
C. heart
D. lung | Emphysema is a chronic lung disease caused by the breakdown of the lung tissue. Symptoms of emphysema include shortness of breath, especially during exercise, and chronic cough, usually due to cigarette smoking, and wheezing, especially during expiration. Damage to the alveoli ( Figure below ), is not curable. Smoking is the leading cause of emphysema. | D: lung. |
Lactose is a disaccharide consisting of the monomers glucose and what?
Here are the choices:
A. sucrose
B. glycerol
C. galactose
D. fructose | Common disaccharides include lactose, maltose, and sucrose (Figure 3.8). Lactose is a disaccharide consisting of the monomers glucose and galactose. It is found naturally in milk. Maltose, or malt sugar, is a disaccharide formed by a dehydration reaction between two glucose molecules. The most common disaccharide is sucrose, or table sugar, which is composed of the monomers glucose and fructose. | C: galactose. |
Why does photosynthesis not occur in the deep-water zone?
Here are the choices:
A. it is pressurized
B. it is dark
C. it is stagnant
D. it is cold | The deep-water zone is dark so there is no photosynthesis. Most deep-water organisms are scavengers. They feed on dead organisms that fall to the bottom of the lake. Crabs and catfish are two of these types of organisms. Fungi and bacteria are decomposers that live in the deep zone. | B: it is dark. |
What, now former, planet is small, icy, and rocky?
Here are the choices:
A. jupiter
B. neptune
C. pluto
D. mercury | Pluto was different in other ways. The outer planets are all gas giants. Pluto is small, icy, and rocky. Pluto has a diameter of about 2,400 km. It has only about one-fifth the mass of Earth’s Moon. Pluto’s orbit is tilted relative to the other planets. It's orbit is shaped like a long, narrow ellipse. Pluto’s orbit sometimes even passes inside Neptune’s orbit. | C: pluto. |
What process allows plants to convert light energy into sugars and energy for food?
Here are the choices:
A. respiration
B. photosynthesis
C. glycolysis
D. digestion | Chemical reactions are occurring all around you. Plants use sunlight to drive their photosynthetic process and produce energy. Cars and other vehicles burn gasoline in order to power their engines. Batteries use electrochemical reactions to produce energy and power many everyday devices. Many chemical reactions are going on inside you as well, especially during the digestion of food. | B: photosynthesis. |
What is the equation of power released?
Here are the choices:
A. voltage x current
B. amplitude x current
C. detonation x current
D. uptake x current | ; Power released is equal to the voltage multiplied by the current. | A: voltage x current. |
Silencing genes through epigenetic mechanisms is commonly practiced on what type of uncontrolled cells?
Here are the choices:
A. cancer cells
B. neutral cells
C. innoculous cells
D. giving cells | Cancer and Epigenetic Alterations Silencing genes through epigenetic mechanisms is also very common in cancer cells. There are characteristic modifications to histone proteins and DNA that are associated with silenced genes. In cancer cells, the DNA in the promoter region of silenced genes is methylated on cytosine DNA residues in CpG islands. Histone proteins that surround that region lack the acetylation modification that is present when the genes are expressed in normal cells. This combination of DNA methylation and histone deacetylation (epigenetic modifications that lead to gene silencing) is commonly found in cancer. When these modifications occur, the gene present in that chromosomal region is silenced. Increasingly, scientists understand how epigenetic changes are altered in cancer. Because these changes are temporary and can be reversed—for example, by preventing the action of the histone deacetylase protein that removes acetyl groups, or by DNA methyl transferase enzymes that add methyl groups to cytosines in DNA—it is possible to design new drugs and new therapies to take advantage of the reversible nature of these processes. Indeed, many researchers are testing how a silenced gene can be switched back on in a cancer cell to help re-establish normal growth patterns. Genes involved in the development of many other illnesses, ranging from allergies to inflammation to autism, are thought to be regulated by epigenetic mechanisms. As our knowledge of how genes are controlled deepens, new ways to treat diseases like cancer will emerge. | A: cancer cells. |
Along with muscles, what helps the body move with relatively little force?
Here are the choices:
A. joints
B. limbs
C. glands
D. nerves | With the help of muscles, joints allow the body to move with relatively little force. | A: joints. |
What process do all species use to make the next generation?
Here are the choices:
A. differentiation
B. separation
C. variation
D. reproduction | All living things reproduce to make the next generation. Organisms that do not reproduce will go extinct. As a result, there are no species that do not reproduce ( Figure below ). Some organisms reproduce asexually ( asexual reproduction ), especially single-celled organisms, and make identical copies (or clones) of themselves. Other organisms reproduce sexually ( sexual reproduction ), combining genetic information from two parents to make genetically unique offspring. | D: reproduction. |
According to one of einstein's theory, while light consists of particles, it behaves like this.
Here are the choices:
A. tides
B. molecules
C. thermodynamics
D. waves | After Einstein proposed his theory, evidence was discovered to support it. For example, scientists shone laser light through two slits in a barrier made of a material that blocked light. You can see the setup of this type of experiment in the Figure below . Using a special camera that was very sensitive to light, they took photos of the light that passed through the slits. The photos revealed tiny pinpoints of light passing through the double slits. This seemed to show that light consists of particles. However, if the camera was exposed to the light for a long time, the pinpoints accumulated in bands that resembled interfering waves. Therefore, the experiment showed that light seems to consist of particles that act like waves. | D: waves. |
Soil forms where land areas are what?
Here are the choices:
A. flat
B. cool
C. merging
D. solid | Weathered material washes off steep slopes and so does not stay in place to form soil. Soil forms where land areas are flat or gently undulating. | A: flat. |
An estimated 99 percent of the species that have ever lived on earth no longer exist, showing that what event is common?
Here are the choices:
A. over fishing
B. accumulation
C. extinction
D. pollution | Even though large life forms have been very successful on Earth, most of the life forms on Earth today are still prokaryotes—small, relatively simple single-celled organisms. Fossils indicate that many organisms that lived long ago are extinct. Extinction of species is common; in fact, it is estimated that 99% of the species that have ever lived on Earth no longer exist. | C: extinction. |
What type of energy is the energy of moving matter?
Here are the choices:
A. kinetic energy
B. dynamic energy
C. residual energy
D. potential energy | Kinetic energy is the energy of moving matter. Anything that is moving has kinetic energy—from atoms in matter to stars in outer space. Things with kinetic energy can do work. For example, the spinning saw blade in the photo above is doing the work of cutting through a piece of metal. | A: kinetic energy. |
What does bile help to digest ?
Here are the choices:
A. food
B. fat
C. nuts
D. protein | The liver secretes bile acids. Bile acids help digest fat. Some liver bile is secreted directly into the small intestine. | B: fat. |
A gene may have different versions called what?
Here are the choices:
A. locus
B. peptides
C. genomes
D. alleles | Traits are controlled by genes on chromosomes. A gene may have different versions called alleles. | D: alleles. |
Nonvascular plants lack vascular tissue and what?
Here are the choices:
A. cells
B. cytoplasm
C. seeds
D. chlorophyll | Nonvascular plants lack seeds and vascular tissue. | C: seeds. |
What is a mixture of metal with one or more other elements?
Here are the choices:
A. a metalloid
B. an alkali metal
C. a halloid
D. an alloy | An alloy is a mixture of a metal with one or more other elements. The other elements may be metals, nonmetals, or both. An alloy is formed by melting a metal and dissolving the other elements in it. The molten solution is then allowed to cool and harden. Alloys generally have more useful properties than pure metals. Several examples of alloys are described and pictured below. You can learn about another alloy—the amazing alloy called memory wire—at the following URL. If you have braces on your teeth, you might even have this alloy in your mouth!. | D: an alloy. |
Pheromones enable what, which is vital for organisms like ants that live in a large community?
Here are the choices:
A. communication
B. asexual reproduction
C. adaptation
D. migration | Living in a large colony requires good communication. Ants communicate with chemicals called pheromones. For example, an ant deposits pheromones on the ground as it returns to the nest from a food source. It is marking the path so other ants can find the food. Honeybees communicate by doing a “waggle dance. ”. | A: communication. |
What is the part of the shadow that is partially lit called?
Here are the choices:
A. pentila
B. pleura
C. eclipse
D. penumbra | The penumbra is the part of the shadow that is partially lit. | D: penumbra. |
When a mountain stream flows onto flatter land and comes to a stop rapidly, what do the deposits form?
Here are the choices:
A. vertical fan
B. alluvial fan
C. conical fan
D. upstream fan | In arid regions, a mountain stream may flow onto flatter land. The stream comes to a stop rapidly. The deposits form an alluvial fan ( Figure below ). | B: alluvial fan. |
The processes of homeostasis and temperature control are centered in the hypothalamus of the advanced animal brain, thus thermoregulation depends on what organ system?
Here are the choices:
A. nervous system
B. digestive system
C. cardiovascular system
D. circulatory system | Neural Control of Thermoregulation The nervous system is important to thermoregulation, as illustrated in Figure 33.22. The processes of homeostasis and temperature control are centered in the hypothalamus of the advanced animal brain. | A: nervous system. |
Light from objects at different distances is focused by what part of the eye?
Here are the choices:
A. pupil
B. iris
C. meniscus
D. lens | Light from objects at different distances is focused by the lens of the eye. Muscles in the eye control the shape of the lens so the light is focused on the back of the eye no matter how far the object is from the lens. | D: lens. |
Breaking a window with a baseball is an example of what kind of change in matter?
Here are the choices:
A. chemical
B. unusual
C. physical
D. sudden | You hit a baseball out of the park and head for first base. You’re excited. The score is tied, and now your team has a chance of getting a winning home run. Then you hear a crash. Oh no! The baseball hit a window in a neighboring house. The glass has a big hole in it, surrounded by a web of cracks (see Figure below ). The glass has changed. It’s been broken into jagged pieces. But the glass is still glass. Breaking the window is an example of a physical change in matter. | C: physical. |
Scientists will often observe and then what the reason why a phenomenon occurred?
Here are the choices:
A. hypothesize
B. realize
C. normalize
D. theorize | 2.3 Scientific method The scientific method is not a step by step, linear process. It is an intuitive process, a methodology for learning about the world through the application of knowledge. Scientists must be able to have an "imaginative preconception" of what the truth is. Scientists will often observe and then hypothesize the reason why a phenomenon occurred. They use all of their knowledge and a bit of imagination, all in an attempt to uncover something that might be true. A typical scientific investigation might go like so: You observe that a room appears dark, and you ponder why the room is dark. In an attempt to find explanations to this curiosity, your mind unravels several different hypotheses. One hypothesis might state that the lights are turned off. Another hunch might be that the room's lightbulb has burnt out. Worst yet, you could be going blind. To discover the truth, 10 11 12 13 14. | A: hypothesize. |
Similar to the coil on a stove, changes in what reflect an increase in the temperature of a star?
Here are the choices:
A. color
B. texture
C. direction
D. rotation | Think about the coil of an electric stove as it heats up. The coil changes in color as its temperature rises. When you first turn on the heat, the coil looks black. The air a few inches above the coil begins to feel warm. As the coil gets hotter, it starts to glow a dull red. As it gets even hotter, it becomes a brighter red. Next it turns orange. If it gets extremely hot, it might look yellow-white, or even blue-white. Like a coil on a stove, a star’s color is determined by the temperature of the star’s surface. Relatively cool stars are red. Warmer stars are orange or yellow. Extremely hot stars are blue or blue-white. | A: color. |
Proto-oncogenes are positive cell-cycle regulators but when mutated, they can become what?
Here are the choices:
A. oncogenes and cause cancer
B. bacteria and cause cancer
C. cultigens and cause cancer
D. microbes and cause cancer | Watch this animation (http://openstaxcollege. org/l/p53_cancer) to learn more about the use of p53 in fighting cancer. Proto-oncogenes are positive cell-cycle regulators. When mutated, proto-oncogenes can become oncogenes and cause cancer. Overexpression of the oncogene can lead to uncontrolled cell growth. This is because oncogenes can alter transcriptional activity, stability, or protein translation of another gene that directly or indirectly controls cell growth. An example of an oncogene involved in cancer is a protein called myc. Myc is a transcription factor that is aberrantly activated in Burkett’s Lymphoma, a cancer of the lymph system. Overexpression of myc transforms normal B cells into cancerous cells that continue to grow uncontrollably. High B-cell numbers can result in tumors that can interfere with normal bodily function. Patients with Burkett’s lymphoma can develop tumors on their jaw or in their mouth that interfere with the ability to eat. | A: oncogenes and cause cancer. |
When the maximum amount of solute has been dissolved in a given amount of solvent, we say that the solution is what?
Here are the choices:
A. empty
B. used
C. saturated
D. blended | When the maximum amount of solute has been dissolved in a given amount of solvent, we say that the solution is saturated with solute. When less than the maximum amount of solute is dissolved in a given amount of solute, the solution is unsaturated. These terms are also qualitative terms because each solute has its own solubility. A solution of 0.00019 g of AgCl per 100 g of H2O may be saturated, but with so little solute dissolved, it is also rather dilute. A solution of 36.1 g of NaCl in 100 g of H2O is also saturated but rather concentrated. Ideally, we need more precise ways of specifying the amount of solute in a solution. We will introduce such ways in Section 11.2 "Quantitative Units of Concentration". In some circumstances, it is possible to dissolve more than the maximum amount of a solute in a solution. Usually, this happens by heating the solvent, dissolving more solute than would normally dissolve at regular temperatures, and letting the solution cool down slowly and carefully. Such solutions are called supersaturated solutions and are not stable; given an opportunity (such as dropping a crystal of solute in the solution), the excess solute will precipitate from the solution. It should be obvious that some solutes dissolve in certain solvents but not others. NaCl, for example, dissolves in water but not in vegetable oil. Beeswax dissolves in liquid hexane but not water. What is it that makes a solute soluble in some solvents but not others? The answer is intermolecular interactions. The intermolecular interactions include London dispersion forces, dipole-dipole interactions, and hydrogen bonding (as described in Chapter 10 "Solids and Liquids"). From experimental studies, it has been determined that if molecules of a solute experience the Saylor URL: http://www. saylor. org/books. | C: saturated. |
What is the movement of substances across the membrane without the expenditure of cellular energy called?
Here are the choices:
A. immune transport
B. passive transport
C. inner cell transport
D. active transport | membrane are nonpolar). Some examples of these are other lipids, oxygen and carbon dioxide gases, and alcohol. However, water-soluble materials—like glucose, amino acids, and electrolytes—need some assistance to cross the membrane because they are repelled by the hydrophobic tails of the phospholipid bilayer. All substances that move through the membrane do so by one of two general methods, which are categorized based on whether or not energy is required. Passive transport is the movement of substances across the membrane without the expenditure of cellular energy. In contrast, active transport is the movement of substances across the membrane using energy from adenosine triphosphate (ATP). | B: passive transport. |
What energy, produced by vibrations, cannot travel through empty space?
Here are the choices:
A. light
B. heat
C. plasma
D. sound | The drummer in Figure below is hitting the drumheads with drumsticks. This causes the drumheads to vibrate. The vibrations pass to surrounding air particles and then from one air particle to another in a wave of energy called sound energy . We hear sound when the sound waves reach our ears. Sound energy can travel through air, water, and other substances, but not through empty space. That’s because the energy needs particles of matter to pass it on. | D: sound. |
According to rutherford, where is the vast majority of the mass of an atom located?
Here are the choices:
A. the cytoplasm
B. the shell
C. the electrons
D. the nucleus | Rutherford’s experiment showed that the vast majority of the mass of an atom is concentrated in its nucleus, which is composed of protons and neutrons. The mass of an electron is very small compared to the mass of a neutron or proton, so the electrons in an element do not contribute much to the total mass. The mass number is defined as the total number of protons and neutrons in an atom. Remember that both protons and neutrons have a mass of approximately 1 amu. Knowing the mass number and the atomic number of an atom therefore allows you to determine the number of neutrons present in that atom by subtraction:. | D: the nucleus. |
What is the term for organisms that make their own food?
Here are the choices:
A. omnivores
B. autotrophs
C. plastids
D. monocots | Autotrophs are organisms that make their own food. Most autotrophs use the energy in sunlight to make food in a process called photosynthesis . Only three types of organisms—plants, algae, and some bacteria—can make food through photosynthesis. Examples of each type of photosynthetic organism are shown in Figure below . | B: autotrophs. |
What happens to neutral matter when electrons are transferred between objects?
Here are the choices:
A. it stays neutral
B. it becomes charged
C. it dissolves itself
D. osmosis | Whenever electrons are transferred between objects, neutral matter becomes charged. For example, when atoms lose or gain electrons they become charged particles called ions. | B: it becomes charged. |
Seawalls and breakwaters are built parallel to what?
Here are the choices:
A. ocean base
B. the deep
C. center-point
D. shore | Seawalls and breakwaters are built parallel to the shore. | D: shore. |
What is the term for the loss of one or more electrons by an atom?
Here are the choices:
A. decomposition
B. oxidation
C. evaporation
D. half-life | The reactants are two electrically neutral elements; they have the same number of electrons as protons. The product, however, is ionic; it is composed of Mg2+ and Cl−ions. Somehow, the individual Mg atoms lose two electrons to make the Mg2+ ion, while the Cl atoms gain an electron to become Cl− ions. This reaction involves thetransfer of electrons between atoms. The process of losing and gaining electrons occurs simultaneously. However, mentally we can separate the two processes. Oxidation is defined as the loss of one or more electrons by an atom. Reduction is defined as the gain of one or more electrons by an atom. So oxidation and reduction always occur together; it is only mentally that we can separate them. Chemical reactions that involve the transfer of electrons are called oxidation-reduction (or redox) reactions. Redox reactions require that we keep track of the electrons assigned to each atom in a chemical reaction. How do we do that? We use oxidation numbers to keep track of electrons in atoms. Oxidation numbers are assigned to atoms based on four rules. Oxidation numbers are not necessarily equal to the charge on the atom (although sometimes they can be); we must keep the concepts of charge and oxidation numbers separate. The rules for assigning oxidation numbers to atoms are as follows: 1. | B: oxidation. |
What are the lipids containing phosphorus?
Here are the choices:
A. alkaloids
B. phospholipids
C. hemoglobin
D. eukaryotes | plants. Saturated triglycerides are those containing a higher proportion of saturated fatty acid chains (fewer carbon-to-carbon double bonds); unsaturated triglyceridescontain a higher proportion of unsaturated fatty acid chains. Saponification is the hydrolysis of a triglyceride in a basic solution to form glycerol and three carboxylate anions or soap molecules. Other important reactions are the hydrogenation and oxidation of double bonds in unsaturated fats and oils. Phospholipids are lipids containing phosphorus. In phosphoglycerides, the phosphorus is joined to an amino alcohol unit. Some phosphoglycerides, like lecithins, are used to stabilize an emulsion—a dispersion of two liquids that do not normally mix, such as oil and water. Sphingolipids are lipids for which the precursor is the amino alcohol sphingosine, rather than glycerol. A glycolipidhas a sugar substituted at one of the OH groups of either glycerol or sphingosine. All are highly polar lipids found in cell membranes. Polar lipids have dual characteristics: one part of the molecule is ionic and dissolves in water; the rest has a hydrocarbon structure and dissolves in nonpolar substances. Often, the ionic part is referred to as hydrophilic (literally, “water loving”) and the nonpolar part as hydrophobic (“water fearing”). When placed in water, polar lipids disperse into any one of three arrangements: micelles,monolayers, and bilayers. Micelles are aggregations of molecules in which the hydrocarbon tails of the lipids, being hydrophobic, are directed inward (away from the surrounding water), and the hydrophilic heads that are directed outward into the water. Bilayers are double layers arranged so that the hydrophobic tails are sandwiched between the two layers of hydrophilic heads, which remain in contact with the water. Every living cell is enclosed by a cell membrane composed of a lipid bilayer. In animal cells, the bilayer consists mainly of phospholipids, glycolipids, and the steroid cholesterol. Embedded in the bilayer are integral proteins, andperipheral proteins are loosely associated with the surface of the bilayer. Everything between the cell membrane and the membrane of the cell nucleus is called the cytoplasm. | B: phospholipids. |
Ethers readily dissolve what type of molecules?
Here are the choices:
A. polar
B. proteins
C. non-polar
D. lipids | Ethers are good solvents for other organic compounds because of their low reactivity. They readily dissolve non-polar molecules. Diethyl ether is perhaps the best known ether. It is widely used as a solvent and has been used as an inhalable anesthetic. | C: non-polar. |
What are bones made up of?
Here are the choices:
A. platelets
B. muscles
C. tissues
D. molecules | Bones are made up of different types of tissues. | C: tissues. |
When it is winter in the northern hemisphere the southern hemisphere experiences which season?
Here are the choices:
A. spring
B. summer
C. winter
D. autumn | B: summer. | |
What happens when liquid water evaporates?
Here are the choices:
A. condensation
B. humidity happens
C. snow
D. seawater happens | The water cycle plays an important role in weather. When liquid water evaporates, it causes humidity. When water vapor condenses, it forms clouds and precipitation. Humidity, clouds, and precipitation are all important weather factors. | B: humidity happens. |
What vision defect occurs because the eye is too long?
Here are the choices:
A. blindness
B. astigmatism
C. hyperopia
D. myopia | In myopia, the eye is too long. Below, you can see how images are focused on the retina of someone with myopia ( Figure below ). Myopia is corrected with a concave lens, which curves inward like the inside of a bowl. The lens changes the focus, so images fall on the retina as they should. | D: myopia. |
What happens when a neutral atom gains or loses electrons?
Here are the choices:
A. it loses neutrons
B. it gains protons
C. it loses protons
D. it becomes an ion | As we studied in our chapter on the periodic table, we saw that elements share a number of important properties with other elements found in the same group. The chemical behavior of a given element is largely dictated by the configuration of its valence electrons. Many elements have a tendency to gain or lose electrons in order to achieve a more stable configuration. When a neutral atom gains or loses electrons, it becomes an ion. In this lesson, we will look at ways to predict what type of ion a given element is likely to form. | D: it becomes an ion. |
Why are goose feathers preferred for stuffing by manufacturers?
Here are the choices:
A. multi layers build up
B. softness
C. thickness
D. smoothness | Feathers are also used all over the world to stuff pillows, mattresses, sleeping bags, coats, and quilting. Goose feathers are preferred because they are soft. Manufacturers often mix goose feathers with down feathers to provide extra softness. | B: softness. |
What is the outermost part of the sun's atmosphere called?
Here are the choices:
A. rays
B. corona
C. ultraviolet
D. particles | The corona ( Figure below ) is the outermost part of the Sun's atmosphere. It is the Sun’s halo, or “crown. ” With a temperature of 1 to 3 million K, the corona is much hotter than the photosphere. The corona extends millions of kilometers into space. Sometime you should try to see a total solar eclipse. If you do, you will see the Sun’s corona shining out into space. | B: corona. |
What is the series of changes in the life of an organism?
Here are the choices:
A. insect metamorphosis
B. evolution
C. circle of life
D. life cycle | Organisms that have a diploid life cycle spend the majority of their lives as diploid adults. All diploid adults inherit half of their DNA from each parent. When they are ready to reproduce, diploid reproductive cells undergo meiosis and produce haploid gametes. These gametes then fuse through fertilization and produce a diploid zygote, which immediately enters G 1 of the cell cycle. Next, the zygote's DNA is replicated. Finally, the processes of mitosis and cytokinesis produce two genetically identical diploid cells. Through repeated rounds of growth and division, this organism becomes a diploid adult and the cycle continues. This is the life cycle of humans. | D: life cycle. |
The outer planets are made of hydrogen and helium, so they are termed what?
Here are the choices:
A. light giants
B. hydrogen giants
C. gas giants
D. helium giants | The outer planets are made of hydrogen and helium, so they are called gas giants. | C: gas giants. |
When a liquid is heated, molecules with enough kinetic energy escape the liquid and become what?
Here are the choices:
A. vapor
B. invisible
C. solid
D. atoms | Kinetic energy distribution curves for a liquid at two temperatures T 1 and T 2 . The shaded area is the molecules with enough kinetic energy to escape the liquid and become vapor. | A: vapor. |
What property of an object is obtained by multiplying its mass and its velocity?
Here are the choices:
A. momentum
B. movement
C. component
D. fluid | When skater 2 runs into skater 1, he’s going faster than skater 1 so he has more momentum. Momentum is a property of a moving object that makes it hard to stop. It’s a product of the object’s mass and velocity. At the moment of the collision, skater 2 transfers some of his momentum to skater 1, who shoots forward when skater 2 runs into him. Whenever an action and reaction such as this occur, momentum is transferred from one object to the other. However, the combined momentum of the objects remains the same. In other words, momentum is conserved. This is the law of conservation of momentum . | A: momentum. |
Solutions that are prepared in which a solute concentration exceeds its solubility are called what?
Here are the choices:
A. supersaturated
B. instantiated
C. mineralized
D. solidified | Solutions may be prepared in which a solute concentration exceeds its solubility. Such solutions are said to be supersaturated, and they are interesting examples of nonequilibrium states. For example, the carbonated beverage in an open container that has not yet “gone flat” is supersaturated with carbon dioxide gas; given time, the CO2 concentration will decrease until it reaches its equilibrium value. | A: supersaturated. |
The word fungus comes from the latin word for what?
Here are the choices:
A. vegetable
B. mushroom
C. spore
D. mold | Introduction The word fungus comes from the Latin word for mushrooms. Indeed, the familiar mushroom is a reproductive structure used by many types of fungi. However, there are also many fungi species that don't produce mushrooms at all. Being eukaryotes, a typical fungal cell contains a true nucleus and many membrane-bound organelles. The kingdom Fungi includes an enormous variety of living organisms collectively referred to as Eucomycota, or true Fungi. While scientists have identified about 100,000 species of fungi, this is only a fraction of the 1.5 million species of fungus likely present on Earth. Edible mushrooms, yeasts, black mold, and the producer of the antibiotic penicillin, Penicillium notatum, are all members of the kingdom Fungi, which belongs to the domain Eukarya. Fungi, once considered plant-like organisms, are more closely related to animals than plants. Fungi are not capable of photosynthesis: they are heterotrophic because they use complex organic compounds as sources of energy and carbon. Some fungal organisms multiply only asexually, whereas others undergo both asexual reproduction and sexual reproduction with alternation of generations. Most fungi produce a large number of spores, which are haploid cells that can undergo mitosis to form multicellular, haploid individuals. Like bacteria, fungi play an essential role in ecosystems because they are decomposers and participate in the cycling of nutrients by breaking down organic materials to simple molecules. Fungi often interact with other organisms, forming beneficial or mutualistic associations. For example most terrestrial plants form symbiotic relationships with fungi. The roots of the plant connect with the underground parts of the fungus forming mycorrhizae. Through mycorrhizae, the fungus and plant exchange nutrients and water, greatly aiding the survival of both species Alternatively, lichens are an association between a fungus and its photosynthetic partner (usually an alga). Fungi also cause serious infections in plants and animals. For example, Dutch elm disease, which is caused by the fungus Ophiostoma ulmi, is a particularly devastating type of fungal infestation that destroys many native species of elm (Ulmus sp. ) by infecting the tree’s vascular system. The elm bark beetle acts as a vector, transmitting the disease from tree to tree. | B: mushroom. |
The part of a plant that is responsible for reproduction is the?
Here are the choices:
A. leaf
B. flower
C. root
D. stem | B: flower. | |
Isotopes have the same number of protons and electrons, but a different number of what?
Here are the choices:
A. reactions
B. neutrons
C. impurities
D. atoms | Isotopes have the same number of protons and electrons, but a different number of neutrons. | B: neutrons. |
Shivering and adipose tissue called brown fat are used by mammals in particular to produce what?
Here are the choices:
A. energy
B. heat
C. nutrition
D. blood | Many animals, especially mammals, use metabolic waste heat as a heat source. When muscles are contracted, most of the energy from the ATP used in muscle actions is wasted energy that translates into heat. Severe cold elicits a shivering reflex that generates heat for the body. Many species also have a type of adipose tissue called brown fat that specializes in generating heat. | B: heat. |
Where are the somas of sensory neurons located in the spinal cord?
Here are the choices:
A. dorsal root ganglia
B. penetration root ganglia
C. frontal root ganglia
D. frontal head ganglia | Figure 35.29 Spinal nerves contain both sensory and motor axons. The somas of sensory neurons are located in dorsal root ganglia. The somas of motor neurons are found in the ventral portion of the gray matter of the spinal cord. | A: dorsal root ganglia. |
The thick tunica media allows muscular arteries to play a leading role in what?
Here are the choices:
A. accumulation
B. inhibition
C. vasodilation
D. vasoconstriction | Farther from the heart, where the surge of blood has dampened, the percentage of elastic fibers in an artery’s tunica intima decreases and the amount of smooth muscle in its tunica media increases. The artery at this point is described as a muscular artery. The diameter of muscular arteries typically ranges from 0.1 mm to 10 mm. Their thick tunica media allows muscular arteries to play a leading role in vasoconstriction. In contrast, their decreased quantity of elastic fibers limits their ability to expand. Fortunately, because the blood pressure has eased by the time it reaches these more distant vessels, elasticity has become less important. Notice that although the distinctions between elastic and muscular arteries are important, there is no “line of demarcation” where an elastic artery suddenly becomes muscular. Rather, there is a gradual transition as the vascular tree repeatedly branches. In turn, muscular arteries branch to distribute blood to the vast network of arterioles. For this reason, a muscular artery is also known as a distributing artery. | D: vasoconstriction. |
Why do crystals have relatively sharp and well-defined melting points?
Here are the choices:
A. uniform intermolecular forces
B. angular intermolecular forces
C. variable intermolecular forces
D. particular intermolecular forces | Deformation of the ionic crystal causes one plane of atoms to slide along another. The resulting repulsive interactions between ions with like charges cause the layers to separate. Crystals tend to have relatively sharp, well-defined melting points because all the component atoms, molecules, or ions are the same distance from the same number and type of neighbors; that is, the regularity of the crystalline lattice creates local environments that are the same. Thus the intermolecular forces holding the solid together are uniform, and the same amount of thermal energy is needed to break every interaction simultaneously. Amorphous solids have two characteristic properties. When cleaved or broken, they produce fragments with irregular, often curved surfaces; and they have poorly defined patterns when exposed to x-rays because their components are not arranged in a regular array. An amorphous, translucent solid is called a glass. Almost any substance can solidify. | A: uniform intermolecular forces. |
In which area does conduction mainly happen?
Here are the choices:
A. mesosphere
B. higher atmosphere
C. thermosphere
D. lower atmosphere | In conduction , heat is transferred from molecule to molecule by contact. Warmer molecules vibrate faster than cooler ones. They bump into the cooler molecules. When they do, they transfer some of their energy. Conduction happens mainly in the lower atmosphere. Can you explain why?. | D: lower atmosphere. |
What is secreted by the cells surrounding spermatogonia to help sperm production?
Here are the choices:
A. estrogen
B. dihydrotestosterone
C. testosterone
D. follicle stimulating hormone | Seminiferous tubules can be seen in a cross section of a testis pictured in Figure below . The tubule is lined with spermatogonia, which are diploid, sperm-producing cells. Surrounding the spermatogonia are other cells. Some of these other cells secrete substances to nourish sperm, and some secrete testosterone, which is needed for sperm production. | C: testosterone. |
Chemical reactions either require or release what?
Here are the choices:
A. electricity
B. enzymes
C. light
D. energy | Chemical reactions either require energy or release energy. The amount of energy needed or released depends upon the structure of the molecules that are involved in the reaction. Some reactions need to be heated for long periods of time in order for change to take place. Other reactions release energy, allowing heat to be given off to the surroundings. | D: energy. |
Energy that is released when a chemical reaction takes place is known as what?
Here are the choices:
A. liquid energy
B. chemical energy
C. thermal energy
D. consequence energy | B: chemical energy. | |
What is the largest object in the solar system?
Here are the choices:
A. jupiter
B. the orbit
C. the sun
D. the earth | The Sun is just an average star compared to other stars. But it is by far the largest object in the solar system. The Sun is more than 500 times the mass of everything else in the solar system combined! Listed below is data on the sizes of the Sun and planets relative to Earth ( Table below ). | C: the sun. |
In ovoviviparous fish like shark, what develops inside the mother’s body but without nourishment from the mother?
Here are the choices:
A. molecules
B. eggs
C. genes
D. spores | Nearly all fish reproduce sexually, and most species have separate sexes. Those without separate sexes avoid self-fertilization by producing sperm and eggs at different times. Each fish typically produces a large number of gametes. In most fish species, fertilization takes place externally. These fish are oviparous. Eggs are laid and embryos develop outside the mother’s body. In a minority of fish, including sharks, eggs develop inside the mother’s body but without nourishment from the mother. These fish are ovoviviparous. | B: eggs. |
What is the term for a technique used to separate out homogeneous mixtures in which one or more solids are dissolved in a liquid?
Here are the choices:
A. evaporation
B. distillation
C. transpiration
D. absorption | Evaporation is a technique used to separate out homogeneous mixtures in which one or more solids are dissolved in a liquid. Typically, the mixture is heated until all of the liquid has vaporized, leaving behind the dissolved solids ( Figure below ). The vapor can also be captured and recondensed into a liquid if desired. | A: evaporation. |
How do basal mammals like monotreme reproduce?
Here are the choices:
A. budding
B. cloning
C. by laying eggs
D. live birth | Monotremes reproduce by laying eggs. They have a cloaca instead of a uterus and vagina. The eggs pass through the opening of the cloaca. This form of reproduction is the least risky for the mother. However, eggs are harder to protect than is an embryo or a fetus in a pouch or uterus. Therefore, monotreme offspring may have a lower chance of surviving than the offspring of therian mammals. | C: by laying eggs. |
Abundant in unpolluted ponds and streams, planarians prey on smaller animals or feed on?
Here are the choices:
A. unidentified animals
B. algae
C. dead animals
D. fungi | C: dead animals. | |
What does parasitic mean?
Here are the choices:
A. welcome guest
B. lives in host
C. mutual benefit
D. symbiotic | Other types of flatworms are parasitic. That means they live inside another organism, called a host, in order to get the food and energy they need. For example, tapeworms have a head-like area with tiny hooks and suckers (known as the scolex ) that help the worm attach to the intestines of an animal host ( Figure below ). There are over 11,000 species of parasitic flatworms. | B: lives in host. |
What scientist constructed a tree diagram, separating living organisms into three domains?
Here are the choices:
A. carl woese
B. Mendel
C. Gibbs
D. CT Fletcher | Figure 1.17 This phylogenetic tree was constructed by microbiologist Carl Woese using data obtained from sequencing ribosomal RNA genes. The tree shows the separation of living organisms into three domains: Bacteria, Archaea, and Eukarya. Bacteria and Archaea are prokaryotes, single-celled organisms lacking intracellular organelles. (credit: Eric Gaba; NASA Astrobiology Institute). | A: carl woese. |
Most of the genes in the eukaryotic cell are found where?
Here are the choices:
A. the cell wall
B. the mitochondria
C. the nucleus
D. the vacuoles | C: the nucleus. | |
What are known as the building blocks of proteins?
Here are the choices:
A. bases
B. protein acids
C. amino acids
D. organism acids | Introduction Since the rediscovery of Mendel’s work in 1900, the definition of the gene has progressed from an abstract unit of heredity to a tangible molecular entity capable of replication, expression, and mutation (Figure 15.1). Genes are composed of DNA and are linearly arranged on chromosomes. Genes specify the sequences of amino acids, which are the building blocks of proteins. In turn, proteins are responsible for orchestrating nearly every function of the cell. Both genes and the proteins they encode are absolutely essential to life as we know it. | C: amino acids. |
What are the three types of muscle tissue in the body?
Here are the choices:
A. skeletal, cardiac, smooth
B. proliferating , cardiac , smooth
C. topography , cardiac , smooth
D. spongy, cardiac, skeletal | 10.1 Overview of Muscle Tissues Muscle is the tissue in animals that allows for active movement of the body or materials within the body. There are three types of muscle tissue: skeletal muscle, cardiac muscle, and smooth muscle. Most of the body’s skeletal muscle produces movement by acting on the skeleton. Cardiac muscle is found in the wall of the heart and pumps blood through the circulatory system. Smooth muscle is found in the skin, where it is associated with hair follicles; it also is found in the walls of internal organs, blood vessels, and internal passageways, where it assists in moving materials. | A: skeletal, cardiac, smooth. |
The white mountains in new hampshire are part of what province?
Here are the choices:
A. montreal
B. geologic
C. antarctic
D. appalachian | The White Mountains in New Hampshire are part of the Appalachian province. The mountains are only around 6,000 feet high. | D: appalachian. |
What is the ratio of the uncertainty to the measured value, multiplied by one-hundred called?
Here are the choices:
A. percent inconsistency
B. amount uncertainty
C. variable uncertainty
D. percent uncertainty | To express the uncertainty in a measurement, we can calculate percent uncertainty . Percent uncertainty is the ratio of the uncertainty to the measured value, multiplied by one-hundred. For instance, the percent uncertainty associated with the measurement of (52.9 ± 0.5 mL), would be. | D: percent uncertainty. |
What is produced by the sebaceous glands?
Here are the choices:
A. pheromone
B. progesterone
C. sebum
D. sperm | Structures in the dermis include hair follicles and sebaceous glands, which produce sebum. | C: sebum. |
What do you call vesicle transport into the cell?
Here are the choices:
A. dialysis
B. metastasis
C. endocytosis
D. passive transport | Vesicle transport into the cell is called endocytosis. The cell membrane engulfs the substance. Then a vesicle pinches off from the membrane and carries the substance into the cell. | C: endocytosis. |
What are daily changes in the level of ocean water called?
Here are the choices:
A. currents
B. tides
C. floods
D. waves | Tides are daily changes in the level of ocean water. They are caused mainly by the pull of the Moon’s gravity on Earth and its oceans. The Sun’s gravity also influences tides. | B: tides. |
What is the name of the narrow tube that begins at the stomach and ends at the large intestine?
Here are the choices:
A. small tissues
B. small intestine
C. small stomach
D. pancreas | The small intestine is a narrow tube that starts at the stomach and ends at the large intestine. In adults, it’s about 7 meters (23 feet) long. Most chemical digestion and almost all nutrient absorption take place in the small intestine. | B: small intestine. |
What is the term for how close a measurement is to the true value?
Here are the choices:
A. correctness
B. accuracy
C. validity
D. frequency | Accuracy is how close a measurement is to the true value. For example, 66 mL is a fairly accurate measurement of the liquid in Figure above . | B: accuracy. |
What are the two most abundant elements in the universe?
Here are the choices:
A. hydrogen and helium
B. nitrogen and carbon
C. hydrogen and oxygen
D. oxygen and carbon | Hydrogen and helium are the most abundant elements in the universe. | A: hydrogen and helium. |
What is the term for a close relationship between two species in which at least one species benefits.
Here are the choices:
A. endosymbiosis
B. candiasis
C. symbiosis
D. extosis | Symbiosis is a close relationship between two species in which at least one species benefits. Types of symbiosis include mutualism, parasitism, and commensalism. | C: symbiosis. |
Atomic emission spectra are produced when excited electrons return to what state?
Here are the choices:
A. work state
B. side state
C. orbital state
D. ground state | Atomic emission spectra are produced when excited electrons return to ground state. | D: ground state. |
The lungs perform gas exchange using air and what fluid, which is coming and going from the heart?
Here are the choices:
A. blood
B. water
C. saliva
D. mucus | Blood Supply The major function of the lungs is to perform gas exchange, which requires blood from the pulmonary circulation. This blood supply contains deoxygenated blood and travels to the lungs where erythrocytes, also known as red blood cells, pick up oxygen to be transported to tissues throughout the body. The pulmonary artery is an artery that arises from the pulmonary trunk and carries deoxygenated, arterial blood to the alveoli. The pulmonary artery branches multiple times as it follows the bronchi, and each branch becomes progressively smaller in diameter. One arteriole and an accompanying venule supply and drain one pulmonary lobule. As they near the alveoli, the pulmonary arteries become the pulmonary capillary network. The pulmonary capillary network consists of tiny vessels with very thin walls that lack smooth muscle fibers. The capillaries branch and follow the bronchioles and structure of the alveoli. It is at this point that the capillary wall meets the alveolar wall, creating the respiratory membrane. Once the blood is oxygenated, it drains from the alveoli by way of multiple pulmonary veins, which exit the lungs through the hilum. | A: blood. |
In addition to glucose, what gas is used during cellular respiration?
Here are the choices:
A. oxygen
B. nitrogen
C. methane
D. hydrogen | Cellular respiration uses oxygen in addition to glucose. It releases carbon dioxide and water as waste products. Cellular respiration actually "burns" glucose for energy. However, it doesn't produce light or intense heat like burning a candle or log. Instead, it releases the energy slowly, in many small steps. The energy is used to form dozens of molecules of ATP. | A: oxygen. |
Which germ layers are essential for animal embryos to grow and develop into a body?
Here are the choices:
A. histone and melatonin
B. cytoplasm and chloroplasm
C. keratinocytes , ectoderm , mesoderm
D. endoderm, ectoderm, mesoderm | The three germ layers are the endoderm, the ectoderm, and the mesoderm. Cells in each germ layer differentiate into tissues and embryonic organs. The ectoderm gives rise to the nervous system and the epidermis, among other tissues. The mesoderm gives rise to the muscle cells and connective tissue in the body. The endoderm gives rise to the gut and many internal organs. Organogenesis Gastrulation leads to the formation of the three germ layers that give rise during further development to the different organs in the animal body. This process is called organogenesis. Organs develop from the germ layers through the process of differentiation. During differentiation, the embryonic stem cells express specific sets of genes that will determine their ultimate cell type. For example, some cells in the ectoderm will express the genes specific to skin cells. As a result, these cells will take on the shape and characteristics of epidermal cells. The process of differentiation is regulated by location-specific chemical signals from the cell’s embryonic environment that sets in play a cascade of events that regulates gene expression. | D: endoderm, ectoderm, mesoderm. |
Scrubbers and catalytic converters are examples of technologies that change what into harmless compounds?
Here are the choices:
A. mutations
B. toxins
C. pollutants
D. contaminants | Some of the pollutants from fossil fuels can be filtered out of exhaust before it is released into the air ( Figure below ). Other pollutants can be changed to harmless compounds before they are released. Two widely used technologies are scrubbers and catalytic converters. | C: pollutants. |
What is the weighted average of the masses of all isotopes of an element called?
Here are the choices:
A. cell mass
B. light mass
C. atomic mass
D. weight mass | The atomic mass is the weighted average of the masses of all isotopes of an element. | C: atomic mass. |
The ability of a water spider to walk across a body of water is an example of what?
Here are the choices:
A. magnetism
B. high density
C. low gravity
D. surface tension | The surface tension of water is illustrated by a number of common occurrences. For example, water spiders are able to walk across bodies of water because of surface tension. Even though the spiders are denser than water, they do not sink, because the small amount of weight pressing down on the surface is not enough to break the strong hydrogen bonds that hold the surface together. | D: surface tension. |
What are compounds with the same molecular formula but different structures and properties called?
Here are the choices:
A. isomers
B. polymers
C. substrates
D. monomers | A: isomers. |
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