questions stringlengths 37 1.22k | reasoning stringlengths 0 3.56k ⌀ | answers stringlengths 4 138 |
|---|---|---|
The volume of a regularly shaped solid can be calculated from its what?
Here are the choices:
A. density
B. layers
C. dimensions
D. mass | The volume of a regularly shaped solid can be calculated from its dimensions. For example, the volume of a rectangular solid is the product of its length, width, and height. | C: dimensions. |
What is approximately the average stroke volume in humans?
Here are the choices:
A. 70 ml
B. 80 ml
C. 75 ml
D. 65 ml | A: 70 ml. | |
Systemic communication through the phloem helps integrate the functions of the whole what?
Here are the choices:
A. bird
B. insect
C. plant
D. animal | C: plant. | |
What structure shows the bonding between atoms, with dots representing available electrons?
Here are the choices:
A. Mendelian model
B. Pascal model
C. lewis structure
D. string theory | Draw the Lewis electron dot diagram for each substance. Double or triple bonds may be needed. | C: lewis structure. |
What is a thick, dark brown or black liquid found in rock layers of the earth's crust?
Here are the choices:
A. propane
B. coal
C. oil
D. fossil fuel | Oil is a thick, dark brown or black liquid. It is found in rock layers of Earth's crust. Oil is currently the most commonly used source of energy in the world. | C: oil. |
What are indestructible and constantly in motion?
Here are the choices:
A. atoms
B. crystals
C. viruses
D. ions | Atoms are indestructible and constantly in motion. | A: atoms. |
What kind of reaction do you see when the concentration of reactants is higher?
Here are the choices:
A. faster reaction rate
B. constant reaction rate
C. regular reaction rate
D. slow reaction rate | Concentration is the number of particles of a substance in a given volume. When the concentration of reactants is higher, the reaction rate is faster. At higher concentrations, particles of reactants are crowded closer together, so they are more likely to collide and react. Did you ever see a sign like the one in the Figure below ? You might see it where someone is using a tank of pure oxygen for a breathing problem. Combustion, or burning, is a chemical reaction in which oxygen is a reactant. A greater concentration of oxygen in the air makes combustion more rapid if a fire starts burning. | A: faster reaction rate. |
What part of a plant protects the plant cell, maintains its shape, and prevents excessive uptake of water?
Here are the choices:
A. stem
B. wall
C. chloroplasm
D. root | B: wall. | |
The process of splitting atoms creates what kind of waste?
Here are the choices:
A. safe
B. radioactive
C. inert
D. recyclable | Nuclear power is clean. It does not pollute the air. However, the use of nuclear energy does create other environmental problems. Uranium must be mined ( Figure below ). The process of splitting atoms creates radioactive waste. This waste may be dangerous for thousands or hundreds of thousands of years. As yet, there is no long-term solution for storing the radioactive waste. | B: radioactive. |
Chromosomal alterations are mutations that change what?
Here are the choices:
A. chromosome structure
B. discovery structure
C. Skeleton Structure
D. detected structure | Chromosomal alterations are mutations that change chromosome structure. They occur when a section of a chromosome breaks off and rejoins incorrectly or does not rejoin at all. Possible ways these mutations can occur are illustrated in Figure below . Go to this link for a video about chromosomal alterations: http://www. youtube. com/watch?v=OrXRSqa_3lU (2:18). | A: chromosome structure. |
When an atom gains or loses an electron it becames an?
Here are the choices:
A. ion
B. electron
C. photon
D. neutron | Sometimes atoms lose or gain electrons. Then they become ions . Ions have a positive or negative charge. That’s because they do not have the same number of electrons as protons. If atoms lose electrons, they become positive ions, or cations. If atoms gain electrons, they become negative ions, or anions. | A: ion. |
What is a type of cell that supports neurons and maintains their environment?
Here are the choices:
A. neurofilament cell
B. interneuron cell
C. axon cell
D. glial cell | Figure 35.7 Glial cells support neurons and maintain their environment. Glial cells of the (a) central nervous system include oligodendrocytes, astrocytes, ependymal cells, and microglial cells. Oligodendrocytes form the myelin sheath around axons. Astrocytes provide nutrients to neurons, maintain their extracellular environment, and provide structural support. Microglia scavenge pathogens and dead cells. Ependymal cells produce cerebrospinal fluid that cushions the neurons. Glial cells of the (b) peripheral nervous system include Schwann cells, which form the myelin sheath, and satellite cells, which provide nutrients and structural support to neurons. | D: glial cell. |
The coordinated activities of the legume and the rhizobium bacteria depend on what between the partners?
Here are the choices:
A. fertilizer signals
B. chemical signals
C. sight signals
D. electric signals | B: chemical signals. | |
The purpose of scientific investigations generally is to test a what?
Here are the choices:
A. suggestion
B. question
C. hypothesis
D. theory | Although this cartoon pokes fun at scientific hypotheses, the concept of hypothesis is one of the most important in science. Scientific investigations discover evidence that helps science advance, and the purpose of scientific investigations generally is to test hypotheses. Finding evidence to support or disprove hypotheses is how science advances. | C: hypothesis. |
The most common curved mirrors are what?
Here are the choices:
A. convex
B. concave
C. spherical
D. solid | Reflecting surfaces do not have to be flat. The most common curved mirrors are spherical. A spherical mirror is called a concave mirror if the center of the mirror is further from the viewer than the edges are. A spherical mirror is called a convex mirror if the center of the mirror is closer to the viewer than the edges are. | C: spherical. |
What type of tissue covers the outside of a plant in a single layer of cells called the epidermis?
Here are the choices:
A. dermal
B. anterior
C. dorsal
D. mucous | The three types of plant cells are found in each of the major types of plant tissues: dermal, ground, and vascular tissues. Dermal tissue covers the outside of a plant in a single layer of cells called the epidermis. It mediates most of the interactions between a plant and its environment. Ground tissue makes up most of the interior of a plant. It carries out basic metabolic functions and stores food and water. Vascular tissue runs through the ground tissue inside a plant. It consists of bundles of xylem and phloem, which transport fluids throughout the plant. | A: dermal. |
In a molecular compound, electrons are shared between atoms in which type of bond?
Here are the choices:
A. deformation
B. corrosion
C. covalent
D. Ionic | The electron loss and gain is easy to see in a reaction in which ions are formed. However, in many reactions, no such electron transfer occurs. In a molecular compound, electrons are shared between atoms in a type of bond called a covalent bond. Yet it is still common for reactions involving molecular compounds to still be classified as redox reactions. | C: covalent. |
What process does water undergo to leave behind dissolved substances?
Here are the choices:
A. oxidation
B. accumulation
C. ascension
D. evaporation | Minerals form from dissolved substances when water evaporates. | D: evaporation. |
What type of proteins bind to foreign substances and attempt destruction?
Here are the choices:
A. antibodies
B. antigens
C. ribosomes
D. membranes | Proteins play many important roles in living things. Some proteins help cells keep their shape, and some make up muscle tissues. Many proteins speed up chemical reactions in cells. Other proteins are antibodies, which bind to foreign substances such as bacteria and target them for destruction. Still other proteins carry messages or materials. For example, human red blood cells contain a protein called hemoglobin, which binds with oxygen. Hemoglobin allows the blood to carry oxygen from the lungs to cells throughout the body. A model of the hemoglobin molecule is shown in Figure below . | A: antibodies. |
Photosynthesis involves reactions that are dependent on what?
Here are the choices:
A. air
B. light
C. food
D. water | 8.2 | The Light-Dependent Reactions of Photosynthesis By the end of this section, you will be able to: • Explain how plants absorb energy from sunlight • Describe short and long wavelengths of light • Describe how and where photosynthesis takes place within a plant How can light be used to make food? When a person turns on a lamp, electrical energy becomes light energy. Like all other forms of kinetic energy, light can travel, change form, and be harnessed to do work. In the case of photosynthesis, light energy is converted into chemical energy, which photoautotrophs use to build carbohydrate molecules (Figure 8.9). However, autotrophs only use a few specific components of sunlight. | B: light. |
Like simple hormone pathways, hormone cascade pathways typically involve what kind of feedback?
Here are the choices:
A. positive
B. neutral
C. effective
D. negative | D: negative. | |
The ocean basin begins where the ocean meets what?
Here are the choices:
A. river
B. land
C. bay
D. sea | The ocean basin begins where the ocean meets the land. The continental margin begins at the shore and goes down to the ocean floor. It includes the continental shelf, slope, and rise. The continental shelf is part of the continent, but it is underwater today. It is about 100-200 meters deep, much shallower than the rest of the ocean. The continental shelf usually goes out about 100 to 200 kilometers from the shore ( Figure below ). | B: land. |
What causes cobalt chloride to turn pink?
Here are the choices:
A. co 2+ ions
B. discussed 2 + ions
C. h20 + ions
D. show 2 + ions | A solution of cobalt chloride in water is pink due to the presence of the solvated Co 2+ ion. If sufficient HCl is added, the solution turns blue as the CoCl 4 2- ion forms. The reaction can be shifted back to the pink form if more water is added to the solution. | A: co 2+ ions. |
What bodily defense can be acquired in an active or passive way, and can be natural or artificial?
Here are the choices:
A. immunity
B. skin
C. membrane
D. nerves | Immunity can be acquired in an active or passive way, and it can be natural or artificial. Watch this video (http://openstaxcollege. org/l/immunity) to see an animated discussion of passive and active immunity. What is an example of natural immunity acquired passively?. | A: immunity. |
Like the stem, what basic plant structure contains vascular bundles composed of xylem and phloem?
Here are the choices:
A. leaf
B. root
C. flower
D. bark | Like the stem, the leaf contains vascular bundles composed of xylem and phloem (Figure 30.27). The xylem consists of tracheids and vessels, which transport water and minerals to the leaves. The phloem transports the photosynthetic products from the leaf to the other parts of the plant. A single vascular bundle, no matter how large or small, always contains both xylem and phloem tissues. | A: leaf. |
What kind of symmetry do echinoderm larvae have?
Here are the choices:
A. spherical
B. internal
C. radial
D. bilateral | D: bilateral. | |
Reducing waste, as well as reusing and recycling resources, can help save what?
Here are the choices:
A. artificial resources
B. eletrical resources
C. coral resources
D. natural resources | Reducing waste, as well as reusing and recycling resources, can help save natural resources. | D: natural resources. |
What is a person who studies the frequency and distribution of disease within human populations and environments called?
Here are the choices:
A. anthropologist
B. biologist
C. entymologist
D. epidemiologist | Epidemiologist Epidemiology is the study of the occurrence, distribution, and determinants of health and disease in a population. It is, therefore, part of public health. An epidemiologist studies the frequency and distribution of diseases within human populations and environments. Epidemiologists collect data about a particular disease and track its spread to identify the original mode of transmission. They sometimes work in close collaboration with historians to try to understand the way a disease evolved geographically and over time, tracking the natural history of pathogens. They gather information from clinical records, patient interviews, surveillance, and any other available means. That information is used to develop strategies, such as vaccinations (Figure 22.26), and design public health policies to reduce the incidence of a disease or to prevent its spread. Epidemiologists also conduct rapid investigations in case of an outbreak to recommend immediate measures to control it. An epidemiologist has a bachelor’s degree, plus a master’s degree in public health (MPH). Many epidemiologists are also physicians (and have an M. ), or they have a Ph. in an associated field, such as biology or microbiology. | D: epidemiologist. |
In adaptive radiation, what is the name of the initial species that then subsequently becomes multiple other ones?
Here are the choices:
A. Mother
B. father
C. founder
D. pioneer | In some cases, a population of one species disperses throughout an area, and each finds a distinct niche or isolated habitat. Over time, the varied demands of their new lifestyles lead to multiple speciation events originating from a single species, which is called adaptive radiation. From one point of origin, many adaptations evolve causing the species to radiate into several new ones. Island archipelagos like the Hawaiian Islands provide an ideal context for adaptive radiation events because water surrounds each island, which leads to geographical isolation for many organisms (Figure 11.16). The Hawaiian honeycreeper illustrates one example of adaptive radiation. From a single species, called the founder species, numerous species have evolved, including the eight shown in Figure 11.16. | C: founder. |
The structures of both trifluoramine and hydroxylamine are similar to that of what?
Here are the choices:
A. hydrogen
B. ammonia
C. magnesium
D. nitrogen | The structures of both trifluoramine and hydroxylamine are similar to that of ammonia. | B: ammonia. |
What protects reptiles from drying out?
Here are the choices:
A. scales
B. sweat
C. hairs
D. skin | Reptiles also have several adaptations for living on land. They have a skin covered in scales to protect them from drying out. All reptiles have lungs to breathe air. Reptiles are also amniotes , which means their embryos are surrounded by a thin membrane. This membrane protects the embryo from the harsh conditions of living on land. Reptile eggs are also surrounded by a protective shell, which may be either flexible or inflexible. | A: scales. |
How many chromosomes do bacterial dna have?
Here are the choices:
A. one circular chromosome
B. one triangular chromosome
C. one simple chromosome
D. one rectangular chromosome | Bacteria lack many of the structures that eukaryotic cells contain. For example, they don't have a nucleus. They also lack membrane-bound organelles, such as mitochondria or chloroplasts. The DNA of a bacterial cell is also different from a eukaryotic cell. Bacterial DNA is contained in one circular chromosome, located in the cytoplasm. Eukaryotes have several linear chromosomes. Bacteria also have two additional unique features: a cell wall and flagella. Some bacteria also have a capsule outside the cell wall. | A: one circular chromosome. |
What makes blue cheese blue?
Here are the choices:
A. rot
B. fungus
C. mites
D. rennit | Have you ever eaten blue cheese? Do you know what makes it blue? You guessed it. A fungus. For certain types of cheeses, producers add fungal spores to milk curds to promote the growth of mold, which makes the cheese blue. Molds used in cheese production are safe for humans to eat. | B: fungus. |
What type of evolution often happens in species that have symbiotic relationships?
Here are the choices:
A. succession
B. retrogression
C. spontaneous evolution
D. coevolution | Coevolution often happens in species that have symbiotic relationships. Examples include flowering plants and their pollinators. | D: coevolution. |
Helicopter pilots can recover from piloting errors by decreasing altitude, turning some of their potential energy into what kind of energy?
Here are the choices:
A. active
B. free
C. kinetic
D. electrical | Helicopter pilots are quite familiar with rotational kinetic energy. They know, for example, that a point of no return will be reached if they allow their blades to slow below a critical angular velocity during flight. The blades lose lift, and it is impossible to immediately get the blades spinning fast enough to regain it. Rotational kinetic energy must be supplied to the blades to get them to rotate faster, and enough energy cannot be supplied in time to avoid a crash. Because of weight limitations, helicopter engines are too small to supply both the energy needed for lift and to replenish the rotational kinetic energy of the blades once they have slowed down. The rotational kinetic energy is put into them before takeoff and must not be allowed to drop below this crucial level. One possible way to avoid a crash is to use the gravitational potential energy of the helicopter to replenish the rotational kinetic energy of the blades by losing altitude and aligning the blades so that the helicopter is spun up in the descent. Of course, if the helicopter’s altitude is too low, then there is insufficient time for the blade to regain lift before reaching the ground. Problem-Solving Strategy for Rotational Energy 1. Determine that energy or work is involved in the rotation. Determine the system of interest. A sketch usually helps. Analyze the situation to determine the types of work and energy involved. For closed systems, mechanical energy is conserved. That is,. | C: kinetic. |
Rise divided by run is called what?
Here are the choices:
A. mound
B. hill
C. slope
D. steep | Carrying this one step further, we note that the slope of a velocity versus time graph is acceleration. Slope is rise divided by run; on a v vs. t graph, rise = change in velocity Δv and run = change in time Δt . The Slope of v vs. t The slope of a graph of velocity. | C: slope. |
Where did west nile first appear?
Here are the choices:
A. Southeast Asia
B. Central America
C. north america
D. North Africa | The first case of West Nile virus in North America occurred in 1999. Within just a few years, the virus had spread throughout most of the United States. Birds as well as humans can be infected with the virus. Birds often fly long distances. This is one reason why West Nile virus spread so quickly. | C: north america. |
How do cancer cells typically spread from one part of the body to another?
Here are the choices:
A. liver
B. kidneys
C. bloodstream
D. plasma | Sometimes cancer cells break away from a tumor. If they enter the bloodstream, they are carried throughout the body. Then, the cells may start growing in other tissues. This is usually how cancer spreads from one part of the body to another. Once this happens, cancer is very hard to stop or control. | C: bloodstream. |
The rate of the accumulation of neutral what serves as a type of population-based biological clock?
Here are the choices:
A. enzymes
B. eukaryotes
C. polymorphisms
D. prokaryotic | would not be surprised if the surviving populations experienced serious bottlenecks. The subsequent diversification of the surviving organisms, such as the Dinosauria (which includes the extinct dinosaurs and modern birds) and the Cynodontia, which includes the ancestors of modern mammals, including us, could be due in part to these bottleneck-associated effects, for example, through the removal of competing species or predators. An astreroid impact, known as the Cretaceous-Tertiary event, occurred ~65 million years ago; it contributed to the extinction of the dinosaurs and led to the diversification of mammals (which had first appeared in the fossil record ~160 million years ago). While surviving an asteroid impact (or other dramatic changes in climate) may be random, in other cases who survives a bottleneck is not. Consider the effects of a severe drought or highly virulent bacterial or viral infection; the organisms that survive may have specific phenotypes (and associated genotypes) that significantly influence their chance of survival. In such a case, the effect of the bottleneck event would produce non-random changes in the distribution of genotypes (and alleles) in the post-bottleneck population – these selective effects could continue to influence the population in various ways. For example, a trait associated with pathogen resistance may also have negative phenotypic effects. After the pathogen-driven bottleneck, mutations that mitigate the resistance trait's negative effects (and may have their own effects) can be selected. The end result is that traits that would not be selected in the absence of the pathogen, are selected. In addition, the very occurrence of a rapid and extreme reduction in population size has its own effects. For example, it would be expected to increase the effects of genetic drift (see below) and could make finding a mate more difficult. We can identify extreme population reduction events, such as founder effects and bottlenecks, by looking at the variation in genotypes (that is, the sequence of DNA molecules), particularly in genotypic changes not expected to influence phenotypes, mating preference, or reproductive success. These so-called neutral polymorphisms are expected to accumulate in the regions of the genome between genes (intragenic regions) at a constant rate over time (can you suggest why?) The rate of the accumulation of neutral polymorphisms serves as a type of population-based biological clock. Its rate can be estimated, at least roughly, by comparing the genotypes of individuals of different populations whose time of separation can be accurately estimated (assuming of course that there has been no migrations between the populations). Such studies of genomic sequence data (which we will return to later in much greater detail) indicate that the human population arose in Africa ~500,000 years ago. 119 Before this, the population leading to humans is thought to have undergone a bottleneck around ~1.2 million years ago.120 Once established, groups of modern humans migrated within and out of African, undergoing a series of founder effect events between ~45,000 to 60,000 years ago first as they migrated from southern Africa into the regions of the Horn of Africa, then into the Arabian peninsula, and from there into Europe, Asia, Oceania, and finally the Americas. (↓) Comparing genotypes, that is, neutral polymorphisms, between 119. | C: polymorphisms. |
The transmitted light strikes a photoelectric tube, which converts the light energy to?
Here are the choices:
A. color
B. gas
C. heat
D. electricity | D: electricity. | |
About how many grams of carbohydrates are in a typical apple?
Here are the choices:
A. 30
B. 35
C. 20
D. 25 | An apple contains about 20 grams of carbohydrates. How much energy does it provide?. | C: 20. |
What is the smallest unit of a chemical element called?
Here are the choices:
A. droplet
B. cell
C. atom
D. nucleus | An atom is the smallest unit of a chemical element . That is, an atom has all the properties of that element. All atoms of the same element have the same number of protons. | C: atom. |
What is the term for a scalar measure of how quickly an object is moving along this line?
Here are the choices:
A. motion
B. speed
C. force
D. velocity | One dimensional motion describes objects moving in straight lines. Speed is a scalar measure of how quickly an object is moving along this line. Velocity is speed with a direction, making it a vector. If an object’s velocity changes with time, the object is said to be accelerating. When restricted to one dimension, there are only two possible directions for the velocity and acceleration vectors to point in. As we’ll see in the next chapters, understanding an object's acceleration is the key to understanding its motion. | B: speed. |
A redox reaction rearranges what subatomic particles?
Here are the choices:
A. water molecules
B. protons
C. electrons
D. neutrons | A combination reaction makes a new substance from more than one reactant; a redox reaction rearranges electrons. Not all combination reactions are redox reactions, and not all redox reactions are combination reactions. | C: electrons. |
What substances digest the food in the vacuole of an ingestive protist?
Here are the choices:
A. enzymes
B. lipids
C. hormones
D. carbohydrates | Ingestive protists ingest, or engulf, bacteria and other small particles. They extend their cell wall and cell membrane around the food item, forming a food vacuole. Then enzymes digest the food in the vacuole. | A: enzymes. |
What type of force allows non-polar molecules to interact?
Here are the choices:
A. london dispersion
B. centrifigal dispersion
C. graviitational force
D. experienced dispersion | Non-polar molecules can interact by way of London dispersion forces. | A: london dispersion. |
What is a thin layer of bacteria that sticks to a surface?
Here are the choices:
A. a choanocyte
B. a spicule
C. a biolfilm
D. a monofilm | A biofilm is a thin layer of bacteria that sticks to a surface. Cells in a biofilm are all alike, but they may play different roles, such as taking in nutrients or making the “glue” that sticks the biofilm to the surface. The sticky plaque that forms on teeth is a biofilm of bacterial cells. | C: a biolfilm. |
The amount of water vapor in the air and the temperature of the medium affects how fast what travels?
Here are the choices:
A. light
B. colour
C. traffic
D. sound | The speed of sound also depends on the temperature of the medium. For a given medium such as air, sound has a slower speed at lower temperatures. You can compare the speed of sound in air at different temperatures in Table below . A lower temperature means that particles of the medium are moving more slowly, so it takes them longer to transfer the energy of the sound waves. The amount of water vapor in the air affects the speed of sound as well. Do you think sound travels faster or slower when the air contains more water vapor? ( Hint: Compare the speed of sound in water and air in Table above . ). | D: sound. |
An rna codon reading guu encodes for what?
Here are the choices:
A. glycine
B. carbon
C. valine
D. arginine | This chart shows the genetic code used by all organisms. For example, an RNA codon reading GUU would encode for a valine (Val) according to this chart. Start at the center for the first base of the three base codon, and work your way out. Notice that more than one codon may encode for a single amino acid. For example, glycine (Gly) is encoded by a GGG, GGA, GGC, and GGU. Notice there are 64 codons. Of the 64 codons, three are stop codons. | C: valine. |
Scanning acoustic microscopes use what kind of waves to scan a specimen?
Here are the choices:
A. heat waves
B. sound waves
C. gamma waves
D. radio waves | Scanning acoustic microscopes use sound waves to scan a specimen. These microscopes are useful in biology and medical research. | B: sound waves. |
The contents of which organ are mixed every 20 seconds?
Here are the choices:
A. the metabolism
B. kidney
C. the stomach
D. pancreas | C: the stomach. | |
How many chambers are in a reptiles heart?
Here are the choices:
A. ten
B. five
C. three
D. two | Reptiles are a class of ectothermic, tetrapod vertebrates. They have several adaptations for living on dry land, such as tough keratin scales and efficient lungs for breathing air. They also have a three-chambered heart and relatively well-developed brain. | C: three. |
What is the opening in the front of the eye called?
Here are the choices:
A. pupil
B. cornea
C. lens
D. iris | The pupil is an opening in the front of the eye. It looks black because it doesn’t reflect any light. All the light passes through it instead. The pupil controls the amount of light that enters the eye. It automatically gets bigger or smaller to let more or less light in as needed. | A: pupil. |
When salinity and pressure increase, or when temperature decreases, what happens to water density?
Here are the choices:
A. drops
B. increases
C. stays the same
D. fluctuates | Water density increases as salinity and pressure increase, or as temperature decreases. | B: increases. |
The bending of a wave around the edges of an opening or an obstacle is called this?
Here are the choices:
A. diffraction
B. sputtering
C. absorption
D. reflection | contain the carbonyl functional group (C=O; part (a) in Figure 24.14 "The Oxidation State of Carbon in Oxygen- and Nitrogen-Containing Functional Groups"). Alcohols are classified as primary, secondary, or tertiary, depending on whether the –OH group is bonded to a primary, secondary, or tertiary carbon. For example, the compound 5-methyl-3-hexanol is a secondary alcohol. | A: diffraction. |
What controls the shape of a developing zygote early in its development?
Here are the choices:
A. storage genes
B. chromosomes
C. DNA
D. gap genes | Gap genes control the shape of a developing zygote early in its development. Gap mutants are missing segments in their embryos. These genes are highly regulated. | D: gap genes. |
What happens to structural genes in the presence of tryptophan?
Here are the choices:
A. they are not oxidised
B. they are transcribed
C. they are not transcribed
D. they are exterminated | Structure of the trp operon. The trp operon is composed of 5 structural genes, 1 regulatory gene and other regulatory sequences, including the promoter, operator and leader sequence. Within the leader sequence is the attenuator region. In the presence of tryptophan, the structural genes are not transcribed. | C: they are not transcribed. |
What type of pressure may build up inside the cell when water moves into a cell by osmosis?
Here are the choices:
A. pleasurable pressure
B. osmotic pressure
C. transverse pressure
D. impervious pressure | When water moves into a cell by osmosis, osmotic pressure may build up inside the cell. If a cell has a cell wall, the wall helps maintain the cell’s water balance. Osmotic pressure is the main cause of support in many plants. When a plant cell is in a hypotonic environment, the osmotic entry of water raises the turgor pressure exerted against the cell wall until the pressure prevents more water from coming into the cell. At this point the plant cell is turgid ( Figure below ). The effects of osmotic pressures on plant cells are shown in Figure above . | B: osmotic pressure. |
What is the process by which plants make their own food called?
Here are the choices:
A. fusion
B. atherosclerosis
C. photosynthesis
D. fission | C: photosynthesis. | |
Conductivity, oxidation state and physical appearance are properties that help determine whether what are metals?
Here are the choices:
A. organisms
B. atoms
C. elements
D. phases | Strategy: A Based on the conductivity of the elements, determine whether each is a metal, a nonmetal, or a semimetal. Confirm your prediction from its physical appearance. B From the compounds each element forms, determine its common oxidation states. C If the element is a nonmetal, it must be located in the p block of the periodic table. If a semimetal, it must lie along the diagonal line of semimetals from B to At. Transition metals can have two oxidation states separated by one electron. D From your classification, the oxidation states of the element, and its physical appearance, deduce its identity. Solution:. | C: elements. |
What specific part of the brain regulates the endocrine system?
Here are the choices:
A. hypothalamus
B. frontal lobe
C. hippocampus
D. parietal lobe | The endocrine system consists of glands that secrete hormones into the bloodstream. It is regulated by a part of the brain called the hypothalamus, which also secretes hormones. The hypothalamus controls the pituitary gland, which is called the “master gland” of the endocrine system because its hormones regulate other endocrine glands. Other endocrine glands include the thyroid gland and pancreas. | A: hypothalamus. |
Chemical reactions follow which laws?
Here are the choices:
A. thermodynamics
B. Archie's law
C. Physics Analysis
D. Chemical kinetics | Chemical reactions follow the laws of thermodynamics. The First Law of Thermodynamics states that energy can be changed from one form to another, but it cannot be created or destroyed. This law is also known as the Law of Conservation of Energy. The Second Law of Thermodynamics states the energy available after a chemical reaction is always less than that at the beginning of a reaction. This is also commonly referred to as entropy. Entropy can be described as the degree of disorder in a system . That is, as energy is transferred from one form to another, some of the energy is lost as heat, and the amount of available energy decreases. As the energy decreases, the disorder in the system increases, and, by definition, the entropy increases. Ice melting provides an example in which entropy increases. Entropy essentially is a measure of the tendency of a process, such as a chemical reaction, to proceed in a particular direction. | A: thermodynamics. |
There are three basic types of hormones: lipid-derived, amino acid-derived, and what?
Here are the choices:
A. secreted
B. peptide
C. acidic
D. manipulated | CHAPTER SUMMARY 37.1 Types of Hormones There are three basic types of hormones: lipid-derived, amino acid-derived, and peptide. Lipid-derived hormones are structurally similar to cholesterol and include steroid hormones such as estradiol and testosterone. Amino acid-derived hormones are relatively small molecules and include the adrenal hormones epinephrine and norepinephrine. Peptide hormones are polypeptide chains or proteins and include the pituitary hormones, antidiuretic hormone (vasopressin), and oxytocin. | B: peptide. |
Fertilization occurs when an egg and sperm come together to form a what?
Here are the choices:
A. infant
B. zygote
C. eukaryote
D. cell | Fertilization occurs when an egg and sperm come together to form a zygote. | B: zygote. |
The explosion of nitroglycerin, which releases large volumes of gases, is what type of reaction?
Here are the choices:
A. exothermic
B. endothermic
C. exponential
D. energetic | The explosion of nitroglycerin releases large volumes of gases and is very exothermic. | A: exothermic. |
What done ozone help protect against?
Here are the choices:
A. gamma rays
B. helium rays
C. x-rays
D. ultraviolet rays | Ozone (O 3 ) depletion in the atmosphere is of significant concern. This gas serves as a protection against the ultraviolet rays of the sun. Ozone is naturally depleted in addition to the depletion caused by human-made chemicals. The depletion reaction is a two-step process:. | D: ultraviolet rays. |
What category of food includes sugars, starches and fibers?
Here are the choices:
A. enzymes
B. proteins
C. carbohydrates
D. alcohols | Carbohydrates include sugars, starches, and fiber. Sugars and starches are used by the body for energy. One gram of carbohydrates provides 4 Calories of energy. Fiber, which is found in plant foods, cannot be digested but is needed for good health. Simple carbohydrates are small carbohydrates found in foods such as fruits and milk. These carbohydrates include lactose, fructose and glucose. Complex carbohydrates are much larger molecules. Starch, which is a complex carbohydrate found in vegetables and grains, is made of thousands of glucose units bonded together. | C: carbohydrates. |
What are substances that the body needs for energy, building materials, and control of body processes?
Here are the choices:
A. nutrients
B. acids
C. molecules
D. carbons | Nutrients are substances that the body needs for energy, building materials, and control of body processes. Carbohydrates, proteins, lipids, and water are nutrients needed in relatively large amounts. Vitamins and minerals are nutrients needed in much smaller amounts. | A: nutrients. |
What law shows the relationships among temperature, volume, and pressure?
Here are the choices:
A. Newton's law
B. Murphy's Law
C. combined gas
D. Law of Conservation | The combined gas law shows the relationships among temperature, volume, and pressure. | C: combined gas. |
What 2 things keep polar bears warm in their arctic ecosystem?
Here are the choices:
A. thick fur, blubber
B. camouflage, blubber
C. colourful fur , blubber
D. hibernation, thick fur | Thick fur and a layer of blubber keep polar bears warm in their Arctic ecosystem. Why do you think their fur is white? Why might it be an adaptation in an Arctic biome?. | A: thick fur, blubber. |
What two things are a phospholipid molecules composed of?
Here are the choices:
A. hydrophillic head , and adhesion tails
B. hydrophillic head , and hydrophobic tails
C. hemophillic head, and substrate tails
D. hydrophillic head , and substrate tails | Figure 5.3 This phospholipid molecule is composed of a hydrophilic head and two hydrophobic tails. The hydrophilic head group consists of a phosphate-containing group attached to a glycerol molecule. The hydrophobic tails, each containing either a saturated or an unsaturated fatty acid, are long hydrocarbon chains. | B: hydrophillic head , and hydrophobic tails. |
When plants reproduce, the offspring has characteristics similar to the?
Here are the choices:
A. cousins
B. siblings
C. grandparents
D. parents | D: parents. | |
Algae are like plants mainly because they contain what?
Here are the choices:
A. chloroplasts
B. cell wall
C. cells
D. organelles | Algae are like plants mainly because they contain chloroplasts. This allows them to make food by photosynthesis. Algae are important producers in water-based ecosystems such as the ocean. On the other hand, algae lack other plant structures. For example, they don’t have roots, stems, or leaves. Also unlike plants, some algae can move. They may move with pseudopods or flagella. | A: chloroplasts. |
The radius of an atom is defined as one-half the distance between the nuclei in a molecule consisting of two identical atoms joined by what?
Here are the choices:
A. metallic bond
B. ionic bond
C. covalent bond
D. hydrogen bond | Figure 6.31 (a) The radius of an atom is defined as one-half the distance between the nuclei in a molecule consisting of two identical atoms joined by a covalent bond. The atomic radius for the halogens increases down the group as n increases. (b) Covalent radii of the elements are shown to scale. The general trend is that radii increase down a group and decrease across a period. | C: covalent bond. |
What is it called when a mistake occurs in dna replication.
Here are the choices:
A. mutation
B. degradation
C. radiation
D. adaptation | Mutations have many possible causes. Some mutations occur when a mistake is made during DNA replication or transcription. Other mutations occur because of environmental factors. Anything in the environment that causes a mutation is known as a mutagen . Examples of mutagens are shown in Figure below . They include ultraviolet rays in sunlight, chemicals in cigarette smoke, and certain viruses and bacteria. | A: mutation. |
Birds are thought to have evolved around 150 million years ago from what?
Here are the choices:
A. teradactils
B. parrot dinosaurs
C. theropod dinosaurs
D. raptor dinosaurs | Birds are thought to have evolved from theropod dinosaurs around 150 million years ago. | C: theropod dinosaurs. |
The mostly subterranean lifestyle of stone plants reduces water loss from evaporation and inhibits what?
Here are the choices:
A. photosynthesis
B. tissues
C. chlorophyll
D. reactions | A: photosynthesis. | |
What is the term for the process in which an area that has never before been colonized changes through time?
Here are the choices:
A. continuous succession
B. ecological succession
C. environmental succession
D. colony succession | Ecological succession is the process in which a community changes through time. Primary succession occurs in an area that has never before been colonized. Secondary succession occurs in a formerly inhabited area that was disturbed. | B: ecological succession. |
All the major landmasses moved together to form one supercontinent in which period?
Here are the choices:
A. cambrian
B. Mesozoic
C. permian
D. Cenozoic | During the Permian Period, all the major landmasses moved together to form one supercontinent. The supercontinent has been named Pangaea. You can see how it looked in Figure below . At this time, temperatures were extreme and the climate became very dry. As a result, plants and animals evolved ways to cope with dryness. For example, reptiles evolved leathery skin. This helped prevent water loss. Plants evolved waxy leaves for the same purpose. | C: permian. |
A problem with using food chains to describe ecosystems is that some organisms can feed on or be consumed by species from more than one of what level?
Here are the choices:
A. pH level
B. trophic level
C. habitat level
D. biome level | There is a one problem when using food chains to accurately describe most ecosystems. Even when all organisms are grouped into appropriate trophic levels, some of these organisms can feed on species from more than one trophic level; likewise, some of these organisms can be eaten by species from multiple trophic levels. In other words, the linear model of ecosystems, the food chain, is not completely descriptive of ecosystem structure. A holistic model—which accounts for all the interactions between different species and their complex interconnected relationships with each other and with the environment—is a more accurate and descriptive model for ecosystems. A food web is a graphic representation of a holistic, non-linear web of primary producers, primary consumers, and higher-level consumers used to describe ecosystem structure and dynamics (Figure 46.6). | B: trophic level. |
What is the practical application of scientific principles and discoveries to develop things that make our lives easier?
Here are the choices:
A. experiment
B. Movement
C. component
D. engineering | Engineering is the practical application of scientific principles and discoveries to develop things that make our lives easier. Is medicine science or engineering? Justify your answer. | D: engineering. |
In plants, a cell plate is formed during cell cytokinesis by golgi vesicles fusing at the what?
Here are the choices:
A. mitosis plate
B. chromosomes plate
C. metaphase plate
D. tectonic plate | Telophase I and Cytokinesis In telophase, the separated chromosomes arrive at opposite poles. The remainder of the typical telophase events may or may not occur, depending on the species. In some organisms, the chromosomes decondense and nuclear envelopes form around the chromatids in telophase I. In other organisms, cytokinesis—the physical separation of the cytoplasmic components into two daughter cells—occurs without reformation of the nuclei. In nearly all species of animals and some fungi, cytokinesis separates the cell contents via a cleavage furrow (constriction of the actin ring that leads to cytoplasmic division). In plants, a cell plate is formed during cell cytokinesis by Golgi vesicles fusing at the metaphase plate. This cell plate will ultimately lead to the formation of cell walls that separate the two daughter cells. Two haploid cells are the end result of the first meiotic division. The cells are haploid because at each pole, there is just one of each pair of the homologous chromosomes. Therefore, only one full set of the chromosomes is present. This is why the cells are considered haploid—there is only one chromosome set, even though each homolog still consists of two sister chromatids. Recall that sister chromatids are merely duplicates of one of the two homologous chromosomes (except for changes that occurred during crossing over). In meiosis II, these two sister chromatids will separate, creating four haploid daughter cells. | C: metaphase plate. |
What is the type of volcano with a tall cone shape that you picture when picturing a volcano?
Here are the choices:
A. advanced
B. composite
C. inactive
D. active | A composite volcano forms the tall cone shape you usually think of when you think of a volcano. Shield volcanoes are huge, gently sloping volcanoes. Cinder cones are small, cone-shaped volcanoes. | B: composite. |
The amount of what entering the eyes helps control the biological clock?
Here are the choices:
A. energy
B. heat
C. light
D. air | In many species, including humans, circadian rhythms are controlled by a tiny structure called the biological clock . This structure is located in a gland at the base of the brain. The biological clock sends signals to the body. The signals cause regular changes in behavior and body processes. The amount of light entering the eyes helps control the biological clock. The clock causes changes that repeat every 24 hours. | C: light. |
Protists are classified as animal-like, plant-like, or what else?
Here are the choices:
A. bacteria - like
B. virus - like
C. pathogen - like
D. fungus-like | Protists are classified as animal-like, plant-like, or fungus-like. The three groups differ mainly in how they obtain carbon and energy. | D: fungus-like. |
Satellite and schwann cells are the two types of what kind of cell found in the pns?
Here are the choices:
A. glial
B. dendritic
C. epidermal
D. osteoclast | Glial Cells of the PNS One of the two types of glial cells found in the PNS is the satellite cell. Satellite cells are found in sensory and autonomic ganglia, where they surround the cell bodies of neurons. This accounts for the name, based on their appearance under the microscope. They provide support, performing similar functions in the periphery as astrocytes do in the CNS—except, of course, for establishing the BBB. The second type of glial cell is the Schwann cell, which insulate axons with myelin in the periphery. Schwann cells are different than oligodendrocytes, in that a Schwann cell wraps around a portion of only one axon segment and no others. Oligodendrocytes have processes that reach out to multiple axon segments, whereas the entire Schwann cell surrounds just one axon segment. The nucleus and cytoplasm of the Schwann cell are on the edge of the myelin sheath. The relationship of these two types of glial cells to ganglia and nerves in the PNS is seen in Figure 12.12. | A: glial. |
What compound has positive and negative ions?
Here are the choices:
A. covalent
B. protein
C. hydrocarbon
D. ionic | Ionic compounds have positive ions and negative ions. | D: ionic. |
What can be calculated given the mass and speed of an object?
Here are the choices:
A. kinetic energy
B. residual energy
C. harmonic energy
D. systematic energy | Given the mass and speed of an object, calculate its kinetic energy. | A: kinetic energy. |
Earthquakes mark the motions of colliding plates and the locations where plates plunge into what?
Here are the choices:
A. the mesosphere
B. the mantle
C. the core
D. the crust | Convergent plate boundaries also produce strong, deadly earthquakes. Earthquakes mark the motions of colliding plates and the locations where plates plunge into the mantle. These earthquakes can be shallow, intermediate or deep focus. | B: the mantle. |
The ambrosia beetle bores holes in?
Here are the choices:
A. leaves
B. dirt
C. flowers
D. tree bark | Ambrosia beetles bore holes in tree bark and “plant” fungal spores in the holes. The holes in the bark give the fungi an ideal place to grow. The beetles harvest fungi from their “garden. ”. | D: tree bark. |
What effect, related to weather forecasting, occurs not only for sound but for any wave when there is relative motion between the observer and the source?
Here are the choices:
A. echo
B. doppler
C. pulse
D. precipitation | Mole-mole calculations are not the only type of calculations that can be performed using balanced chemical equations. Recall that the molar mass can be determined from a chemical formula and used as a conversion factor. We can add that conversion factor as another step in a calculation to make a molemass calculation, where we start with a given number of moles of a substance and calculate the mass of another substance involved in the chemical equation, or vice versa. For example, suppose we have the balanced chemical equation. | B: doppler. |
What is the science of how traits are passed from parents to offspring?
Here are the choices:
A. genetics
B. alleles
C. cross matching
D. heredity | science of heredity, or how traits are passed from parents to offspring. | D: heredity. |
When an electron transitions from an excited state to a less excited state, or ground state, the difference in energy is emitted as a what?
Here are the choices:
A. nucleus
B. neutron
C. photon
D. quark | which is identical to the Rydberg equation for R ∞ = k . When Bohr calculated his theoretical value for the hc Rydberg constant, R ∞, and compared it with the experimentally accepted value, he got excellent agreement. Since the Rydberg constant was one of the most precisely measured constants at that time, this level of agreement was astonishing and meant that Bohr’s model was taken seriously, despite the many assumptions that Bohr needed to derive it. The lowest few energy levels are shown in Figure 6.14. One of the fundamental laws of physics is that matter is most stable with the lowest possible energy. Thus, the electron in a hydrogen atom usually moves in the n = 1 orbit, the orbit in which it has the lowest energy. When the electron is in this lowest energy orbit, the atom is said to be in its ground electronic state (or simply ground state). If the atom receives energy from an outside source, it is possible for the electron to move to an orbit with a higher n value and the atom is now in an excited electronic state (or simply an excited state) with a higher energy. When an electron transitions from an excited state (higher energy orbit) to a less excited state, or ground state, the difference in energy is emitted as a photon. Similarly, if a photon is absorbed by an atom, the energy of the photon moves an electron from a lower energy orbit up to a more excited one. We can relate the energy of electrons in atoms to what we learned previously about energy. The law of conservation of energy says that we can neither create nor destroy energy. Thus, if a certain amount of external energy is required to excite an electron from one energy level to another, that same amount of energy will be liberated when the electron returns to its initial state (Figure 6.15). In effect, an atom can “store” energy by using it to promote an electron to a state with a higher energy and release it when the electron returns to a lower state. The energy can be released as one quantum of energy, as the electron returns to its ground state (say, from n = 5 to n = 1), or it can be released as two or more smaller quanta as the electron falls to an intermediate state, then to the ground state (say, from n = 5 to n = 4, emitting one quantum, then to n = 1, emitting a second quantum). Since Bohr’s model involved only a single electron, it could also be applied to the single electron ions He+, Li2+, Be3+, and so forth, which differ from hydrogen only in their nuclear charges, and so one-electron atoms and ions are collectively referred to as hydrogen-like atoms. The energy expression for hydrogen-like atoms is a generalization of the hydrogen atom energy, in which Z is the nuclear charge (+1 for hydrogen, +2 for He, +3 for Li, and so on) and k has a value of 2.179 × 10–18 J. E n = − kZ2 n. | C: photon. |
Water from the land and oceans enters the atmosphere by which process?
Here are the choices:
A. condensation
B. absorption
C. transpiration
D. evaporation | Figure 46.14 Water from the land and oceans enters the atmosphere by evaporation or sublimation, where it condenses into clouds and falls as rain or snow. Precipitated water may enter freshwater bodies or infiltrate the soil. The cycle is complete when surface or groundwater reenters the ocean. (credit: modification of work by John M. Evans and Howard Perlman, USGS). | D: evaporation. |
What country put seven salyut space stations into orbit between 1971 and 1982?
Here are the choices:
A. soviet union
B. United States
C. China
D. Japan | Between 1971 and 1982, the Soviets put a total of seven Salyut space stations into orbit. Figure below shows the last of these, Salyut 7. These were all temporary stations. They were launched and later inhabited by a human crew. Three of the Salyut stations were used for secret military purposes. The others were used to study the problems of living in space. Cosmonauts aboard the stations performed a variety of experiments in astronomy, biology, and Earth science. Salyut 6 and Salyut 7 each had two docking ports. One crew could dock a spacecraft to one end. A replacement crew could dock to the other end. | A: soviet union. |
The result of what, in places like the amazon rainforest, is that food will be harder to produce, clean water will be harder to find, and development of new medicines will become slower?
Here are the choices:
A. environmnental loss
B. biological loss
C. biodiversity loss
D. pollution loss | percent of the Amazon rainforest was lost. Rates are higher in other tropical rainforests. What we are likely to notice on a day-to-day basis as a result of biodiversity loss is that food will be more difficult to produce, clean water will be more difficult to find, and the rate of development of new medicines will become slower, as we depend upon other species for much of these services. This increased loss of biodiversity is almost entirely a result of human activities as we destroy species’ habitats, introduce disruptive species into ecosystems, hunt some species to extinction, continue to warm the planet with greenhouse gases, and influence nature in other ways. Slowing the loss of biodiversity is within our abilities if we make dramatic changes in our consumptive behavior and identify and protect the elements of our ecosystems that we depend on for our lives and welfare. | C: biodiversity loss. |
What does rising and sinking air influence in a region?
Here are the choices:
A. precipitation
B. erosion
C. temperature
D. tides | Rising and sinking air can influence the precipitation of a region. | A: precipitation. |
Refracting and reflecting telescopes are optical telescopes that use lenses to gather what?
Here are the choices:
A. electricity
B. sound
C. magnetic force
D. light | Refracting and reflecting telescopes are optical telescopes that use lenses to gather light. | D: light. |
Via what process do substance move from one cell to another?
Here are the choices:
A. reverse transferase
B. downregulation
C. plasmodesmata
D. autolysis | C: plasmodesmata. | |
What is a stellar remnant that is very dense?
Here are the choices:
A. asteroids
B. the sun
C. white dwarf
D. white star | A white dwarf is a stellar remnant that is very dense. A white dwarf's mass is comparable to the Sun and its volume is comparable to that of Earth. The very low brightness of a white dwarf comes from the emission of stored heat energy. | C: white dwarf. |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.