Find study materials for any course. Check these out:
Browse by school
Make your own
To login with Google, please enable popups
To login with Google, please enable popups
Don’t have an account?
To signup with Google, please enable popups
To signup with Google, please enable popups
Sign up withor
2. Which of the following is not a
may be a distinct entity or a building block of a more complex organism.
68. The type of cell that always lacks a cell wall is the _______ cell.
19. _______ are involved in cytoplasmic streaming, in the “pinching” of a cell that ultimately divides an animal cell into two daughter cells, and in the formation of pseudopodia.
15. When a mouse cell and a human cell are fused, the membrane proteins of the two cells become uniformly distributed over the surface of the hybrid cell. This occurs because
a. many proteins can move around within the bilayer.
. Darwin noted that all populations have _______ potential to grow, but that in nature most populations _______ over time.
a group of morphologically similar organisms capable of interbreeding.
The nature and diversity of life have changed over time.
. Earth is approximately _______ years old.
It is thought that the process by which some prokaryotes were consumed by, then integrated into, other prokaryotes took place about _______ years ago.
c. all conversions of matter and energy taking place in an organism.
13. The initial accumulation of oxygen in the atmosphere was the result of photosynthesis from an organism most like modern
14. A prerequisite for the survival of life on land was the accumulation of
15. The chemical formula for ozone is
16. Ozone is important to life on Earth because it
c. blocks much ultraviolet radiation.c. blocks much ultraviolet radiation.
17. Most _______ must obtain their energy from the sun.
18. Plants are
a. eukaryotic, multicellular photosynthesizers.
19. When biologists organize species into groups, they attempt to do so based on
d. degree of relatedness.
20. Scientists group species on an evolutionary tree based on
the fossil record.
b. physical structures.
c. gene similarities.d. All of the above
21. Domain Eukarya includes
b. Kingdom Plantae.
c. Kingdom Fungi.
d. Kingdom Animalia.
e. All of the above
22. An evolutionary tree
a. shows evolutionary relationships.
b. places the most closely related groups on the same branch of the tree.
c. places the organisms that share a common ancestor on the same branch of the tree.
d. shows the order in which populations split and evolved into new species.
e. All of the above
23. The branching patterns of the evolutionary Tree of Life are based on a rich array of evidence from
b. DNA sequencing.
c. metabolic processes.
d. Both a and c
e. All of the above
24. Heterotrophs cannot obtain their energy directly from
25. Members of the kingdom Animalia obtain their energy directly from
c. other organisms.
26. Heterotrophs obtain their energy from
c. other organisms.
27. Which of the following is not a major step in the hypothetico-deductive method?
a. Controlling an environment
28. After observing that fish live in clean water but not in polluted water, you make the statement, “polluted water kills fish.” Your statement is an example of
d. a hypothesis.
29. The key purpose of any single experiment is to
e. test predictions that are based on hypotheses.
30. Which of the following is not a feature of scientific hypotheses?
a. They are unable to be falsified.
31. Which of the following statements about Pieter Johnson’s experiments on frog limb deformities is correct?
a. In a set of comparative experiments, he had to reject his hypothesis that environmental contaminants were causing limb deformities in the frogs.
32. Which of the following statements about the scientific method is correct?
a. Deductive logic is used to make predictions from a hypothesis.
33. The advantage of controlled experiments is that
a. all variables are held constant except one.
34. Which of the following statements is false?
d. Scientists generally conclude that the differences they measure are true if the statistical tests show that the probability of error is 5 percent or lower.
35. Which of the following questions cannot be answered using the hypothetico-deductive method?
b. Are red roses more beautiful than yellow roses?
1. Most living organisms consist of one or more _______, contain _______ that is used to _______ themselves, are genetically related, have _______, and can regulate their _______.
2. _______ are structural, physiological, or behavioral traits that enhance an organism’s chance of survival and reproduction in its environment.
3. Currently, scientists agree with the estimate that life first appeared approximately _______ years ago.
4. Fatlike molecules were the critical ingredient in the enclosure of biological molecules in _______ because these molecules are _______ in water and tend to form membrane-like _______.
5. About _______ years ago, prokaryotes acquired the ability to photosynthesize.
6. Some organelles in eukaryotes can be described as _______ within a cell.
7. In contrast to eukaryotic cells, prokaryotes lack _______.
8. The total chemical activity of a living organism is its _______.
9. Single-celled organisms that lack discrete intracellular compartments belong to the two kingdoms called _______ and _______.
10. There are three domains used to categorize life forms that have evolved separately for about a billion years: _______, _______, and _______.
11. As many as _______ species inhabit Earth.
12. A Pacific tree frog has the scientific nomenclature of Hyla regilla. This particular tree frog belongs to the genus _______.
13. An _______ shows the evolutionary relationships among species.
14. Multicellular organisms that are photosynthetic belong to the kingdom called _______.
15. Fungi and animals are both _______.
16. Nonphotosynthetic multicellular organisms that ingest their food and absorb the products of digestion belong to the kingdom called _______.
17. All scientific study begins with making observations, asking questions, and forming testable _______.
18. The _______ hypothesis states that no difference exists due to the variable under investigation.
1. Probes indicating that there is a dry lake bed and trapped water beneath the poles on Mars are of major significance because they suggest that
2. The part of the atom that determines how the atom behaves chemically is the
3. Which component of an atom does not significantly add to the mass of an atom?
4. What is the difference between an atom and an element?
a. An atom is made of protons, electrons, and sometimes neutrons; an element is a substance composed of only one kind of atom.
5. The number of protons in an atom equals the number of
6. Which of the following statements about atoms is true?
c. When protons equal electrons, an atom has a neutral charge.
7. 3115P and 3215P have virtually identical chemical and biological properties because they have the same
e. number of electrons.
8. An atom that is neutrally charged contains
d. the same number of positive particles as negative particles.
9. Phosphorus has an atomic number of 15 and an atomic weight of 30.974. How many neutrons does phosphorus have?
10. The atomic number of an element is the same as the number of _______ in each atom.
11. The number of different elements found in the universe is closest to
12. The best reference source for the atomic number and mass number of elements is
13. Which of the following elements is contained by all living things?
d. Carbone. All of the above
14. Which of the following pairs has similar chemical properties?
d. 12C and 14C
15. The four elements most common in organisms are
c. carbon, oxygen, hydrogen, and nitrogen.
16. Because atoms can have the same number of protons but a different number of neutrons, elements have
17. An element has a weight of 131.3. The reason the number is not a whole number is that
b. atomic weight is the average of the mass numbers of all the element’s isotopes.
18. Why is the atomic weight of hydrogen 1.008 and not exactly its mass number, 1.000?
b. Atomic weight is the average of the mass numbers of a representative sample of the element, including all its isotopes.
19. The mass number of an atom is determined primarily by the _______ it contains.
d. sum of the number of protons and neutrons
20. Hydrogen, deuterium, and tritium all have the same
21. Of the following atomic configurations, the one that has an atomic mass of 14 is the atom with
22. The ability of atoms to combine with other atoms is determined by
b. the number and distribution of electrons.
23. Phosphorus has an atomic number of 15 and an atomic weight of 30.974. From this information it can be determined that this element
a. has isotopes.
24. The atomic mass of an element is the same as the number of _______ in each atom.
d. protons plus neutrons
25. Which of the following elements is the most chemically reactive?
26. When magnesium (Mg) bonds with another element, you would expect that it would
c. lose two electrons to the other element.
27. All of the elements listed below follow the octet rule except
28. Which of the following statements about the difference between ionic bonds and covalent bonds is true?
b. Electron sharing is more equal in the covalent bond.
29. Which of the following is the correct order (in decreasing order) for the relative strengths of chemical bonds?
a. Covalent, ionic, hydrogen, van der Waals forces
30. In a hydrogen molecule, the two atoms are held together by
b. a shared pair of electrons.
31. What determines if a molecule is polar, nonpolar, or ionic?
c. The differences in the electronegativities of the atoms
32. A single covalent chemical bond represents the sharing of how many electrons?
33. All of the following are nonpolar except
34. Two atoms are held together in four covalent bonds because of forces between the
35. Two carbon atoms held together in a double covalent bond share _______ electron(s).
36. Which of the following atoms usually has the greatest number of covalent bonds with other atoms?
37. Oxygen forms _______ bond(s), carbon forms _______, and hydrogen forms _______.
d. two; four; one
38. A covalent bond is the sharing of _______ between atoms, whereas an ironic bond is the _______.
e. electrons; transfer of electrons from one atom to another
39. Chemical bonds formed by electrical attractions are
40. Ionic bonds are
a. attractions between oppositely charged ions.
41. Particles having a net negative charge are called
42. Which of the following molecules is held together primarily by ionic bonds?
43. Hydrogen bonds
c. form between a strong electronegative atom and hydrogen.
44. Cholesterol is composed primarily of carbon and hydrogen atoms. Therefore, one would expect cholesterol to be
a. insoluble in water.
45. A van der Waals interaction is an attraction between
a. the electrons of a nonpolar molecule and the nucleus of a nearby nonpolar molecule.
46. In addition to covalent and ionic bonds, which of the following interactions are important in biological systems?
van der Waals interactions
b. Hydrogen bonds
c. Hydrophobic interactions
d. Both a and b
e. All of the above
47. The hydrogen bond between two water molecules arises because water is
48. Which of the following correctly states an unusual property of water?
e. The hydrogen bonds between water molecules continually form and break.
49. Two characteristics of water make it different from most other compounds: Its solid state is _______ its liquid state and it takes up _______ heat to change to its gaseous state.
a. less dense than; large amounts of
50. Sweating is a useful cooling device for humans because water
a. takes up a great deal of heat in changing from its liquid state to its gaseous state.
51. When exposed to extreme heat, the human body relies on _______ to absorb excess calories of heat and maintain normal body temperature.
52. Which characteristic of water contributes to the relatively constant temperatures of the oceans?
e. It takes a large amount of heat energy to raise the temperature of water.
53. Ice floats because
a. the crystal takes up more space than the liquid.
54. Ice is used in beverages because
e. it absorbs a lot of heat when it melts.
55. If you place a paper towel in a dish of water, the water will move up the towel by capillary action because water
d. can form hydrogen bonds.
56. Surface tension and capillary action occur in water because it
c. has hydrogen bonds.
57. The molecular weight of water is 18.0154. One mole of water weighs exactly _______ grams.
58. When sodium hydroxide (NaOH) is added to water, it ionizes, releasing OH– and Na+ ions. The resulting solution is
59. H2SO4 can ionize to yield two H+ ions and one SO42– ion. H2SO4 is
e. an acid.
60. Which contains more molecules, a mole of hydrogen or a mole of carbon?
c. Both contain the same number of molecules.
61. The difference between an acid and a base is that an acid _______, whereas a base _______.
e. releases H+ ions in solution; accepts H+ ions
62. To determine the number of molecules in a teaspoon of sugar you need to know
e. the weight and molecular weight of the sugar, and Avogadro’s number.
63. How would you make 100 ml of an aqueous solution with a 0.25 M concentration of a compound that has a molecular weight of 200 daltons?
e. Take 5 grams of the compound and add water until the volume equals 100 ml.
64. Of the following compounds containing 1H, 12C, and 16O, the one with the greatest number of molecules in a sample with a mass of 2 grams would be
65. A basic solution contains
a. more OH– ions than H+ ions.
66. A 1.0 M solution of HCl has a pH of
67. The pH 6.0 contains
e. 10–6 moles of hydrogen ions.
68. The more acidic of two solutions has
c. more H+ ions per liter.
69. Solutions that contain buffers tend to resist pH changes because buffers
c. change from nonionic to ionic in response to changes in pH and release or absorb H+.
70. Acid rain is a serious environmental problem. A sample of rainwater collected in the Adirondack Mountains had an H+ concentration of 10–4 mol/L. The pH of this sample was
71. Carbonic acid and sodium bicarbonate act as buffers in the blood. When a small amount of acid is added to this buffer, the H+ ions are used up as they combine with the bicarbonate ions. When this happens, the pH of the blood
c. does not change.
72. The notation [H+] refers to the
d. concentration of H+ ions in moles per liter.
73. Which of the following has the greatest concentration of hydrogen ions?
e. Cola at pH 3
74. The optimum pH for growing strawberries is 6.5, whereas the optimum pH for growing blueberries is 4.5. Therefore, the number of hydrogen ions needed to grow strawberries is _______ times the number needed for blueberries.
1. One dalton is the same as the mass of one _______.
2. Every atom except for _______ has one or more neutrons in its nucleus.
3. Oxygen and carbon are defined as different elements because they have atoms with a different number of _______.
4. The sum of the atomic weights in any given molecule is called its _______.
5. The chemical properties of an element are determined by the number of _______ its atoms contain.
6. _______ occurs when one atom, such as 14C, is transformed into another atom, such as 14N, with an accompanying emission of energy.
7. The tendency of atoms in stable molecules to have eight electrons in their outermost shells is known as the _______.
8. A _______ is two or more atoms linked by chemical bonds.
10. The electronegativity of an atom depends upon the number of _______ and how far the _______ are from the nucleus.
11. Molecules that have an unequal distribution of electric charge are called _______ molecules.
12. Of the different types of chemical bonds, the strongest bond in biological systems is the _______ bond.
13. The attraction between a slight positive charge on a hydrogen atom and the slight negative charge of a nearby electronegative atom is a _______.
14. In the equation, C6H12O6 Æ 6CO2 + 6H2O, C6H12O6 is the _______.
15. The water strider skates along the surface of water due to a property of liquids called _______.
16. The calories needed to raise one gram of a substance 1°C is known as _______.
17. One mole of a substance contains 6.02 ¥ 1023 molecules. This number is known as_______.
18. A chemical reaction that can proceed in either direction is called a _______.
9. The molecular weight of glucose (C6H12O6) is _______.
1. Large molecules that contain carbon and are held together by covalent bonds are called
3. The bonds that form between the units of polymeric macromolecules are _______ bonds.
4. Which of the following pairs is not a correct monomer/polymer pairing?
5. In condensation reactions, the atoms that make up a water molecule are derived from
c. both of the reactants.
6. Polymerization reactions in which polysaccharides are synthesized from monosaccharides
e. result in the formation of water.
7. During the formation of a peptide linkage, a(n) _______ is formed.
a. molecule of water
8. Polysaccharides, polypeptides, and polynucleotides
b. are broken down in hydrolysis reactions.
9. Amino acids can be classified by the
e. characteristics of their side chains or “R” groups.
10. A protein can best be defined as a polymer
a. of amino acids.
11. Which of the following is characteristic of proteins?
d. Some function as enzymes.
12. The side chain of leucine is a hydrocarbon. In a folded protein, where would you expect to find leucine?
a. In the interior of a cytoplasmic enzyme, b. On the exterior of a protein embedded in a membrane
13. What type of amino acid side chains would you expect to find on the surface of a protein embedded in a cell membrane?
14. Peptide chains have a(n) _______ and a(n) _______ end.
c. N terminus; C terminus
15. What is the theoretical number of different proteins that you could make from 50 amino acids?
16. There are _______ different types of tripeptides (molecules with three amino acids linked together) that can exist using the 20 common amino acids.
17. The shape of a folded protein is often determined by
b. the sequence of its amino acids.
18. The amino acids of the protein keratin are arranged in a helix. This secondary structure is stabilized by
e. hydrogen bonds.
19. The tertiary structure of a protein is determined by its
c. hydrogen bonding.
20. A b pleated sheet organization in a polypeptide chain is an example of _______ structure.
21. Quaternary structure is found in proteins
a. composed of subunits.
22. Enzymes are
23. When a protein loses its three-dimensional structure and becomes nonfunctional it is
24. Incorrect folding of a protein can have serious consequences. For instance, an accumulation of misfolded proteins in the brain is a characteristic of
b. Alzheimer’s disease.
25. Which of the following protein structures is/are destroyed by denaturation?
26. A type of protein that functions by helping other proteins to fold correctly is called a
27. The atoms that make up carbohydrates are
d. C, H, and O.
28. The difference between a- and b-glucose is
b. in the placement of OH and H atoms.
29. A molecule with the formula C16H30O15 is a
30. Glucose and fructose both have the formula C6H12O6, but the atoms in these two compounds are arranged differently. Glucose and fructose are known as
31. The monomers that make up polymeric carbohydrates, like starch are called
32. A simple sugar with the formula C5H10O5 can be classified as a
33. Lactose, or milk sugar, is composed of one glucose unit and one galactose unit. It can be classified as a
34. A type of molecule very often drawn with a single six-sided ring structure is
35. Maltose and lactose are similar in that they both are
36. Sucrose, known as common table sugar, is a
37. DNA and RNA contain
38. A molecule that has an important role in long-term storage of energy is
39. Two important polysaccharides made up of glucose monomers are _______ and _______.
d. cellulose; starch
40. Why does bread become hard and stale?
b. In the absence of water, unbranched starch forms hydrogen bonds between polysaccharides, which then aggregate.
41. In animals, glucose is stored in the compound
42. Starch and glycogen are different in that only one of them
c. is made in plants.
43. Cellulose is the most abundant organic compound on Earth. Its main function is
e. to provide mechanical strength to plant cell walls.
44. Chitin is a polymer of
45. Lipids are
a. insoluble in water.
b. important for energy storage.
d. important constituents of biological membranes.
46. Cholesterol is soluble in ether, an organic solvent, but it is not soluble in water. Based on this information, what class of biological macromolecules does cholesterol belong to?
47. Which of the following is not a function in which lipids play an important role?
48. Which of the following is not a characteristic of lipids?
49. You have isolated an unidentified liquid from a sample of beans. You add the liquid to a beaker of water and shake vigorously. After a few minutes, the water and the other liquid separate into two layers. To which class of large biological molecules does the unknown liquid most likely belong?
51. Lipids form the barriers surrounding various compartments within an organism. Which property of lipids makes them a good barrier?
a. Many biologically important molecules are not soluble in lipids.
52. You look at the label on a container of shortening and see “hydrogenated vegetable oil.” This means that during processing the number of carbon–carbon double bonds in the oil was decreased. What is the result of decreasing the number of double bonds?
b. The oil is now a solid at room temperature.
53. The portion of a phospholipid that contains the phosphorous group has one or more electric charges. That makes this region of the molecule
54. Fatty acids are molecules that
b. are composed of hydrogen, carbon, and a carboxyl group.
55. A fat contains fatty acids and
56. Unsaturated fatty acids do not pack together due to
a. kinks in the hydrocarbon-chain ribozymes.
57. In a biological membrane, the phospholipids are arranged with the fatty acid chains facing the interior
of the membrane. As a result, the interior of the membrane is
58. Waxes are formed by
c. combining fatty acids with alcohol.
59. A nucleotide contains a pentose, a phosphate, and a(n)
c. nitrogen-containing base.
60. The “backbone” of nucleic acid molecules is made of
61. What is the nucleotide sequence of the complementary strand of the DNA molecule: A A T G C G A?
a. T T A C G C T
62. Which of the following is not a difference between DNA and RNA?
d. DNA is a polymer, whereas RNA is a monomer.
63. According to the base-pairing rules for nucleic acids, purines always pair with
64. The four nitrogenous bases of RNA are abbreviated as
e. A, G, C, and U.
65. DNA carries genetic information in its
66. The double helix structure of DNA is due to
d. hydrogen bonding of the two complementary polynucleotide strands.
67. In DNA, A hydrogen bonds with T and G with C; these are examples of a specific type of reaction called
a. complementary base pairing.
68. Examination of meteorites has revealed that they contain the chemistry of life. All of the following have been found in meteorites except
69. Examination of meteorites suggests that
a. life is not limited to Earth.
70. Miller-Urey showed that in any environment with conditions similar to those of Earth,
a. inorganic molecules would react to form organic molecules.
71. Earth’s early atmosphere contained all of the following gases except
72. Spontaneous generation was disproved by
c. Francesco Redi and Louis Pasteur.
73. RNA molecules that act as catalysts are called
1. When chlorine atoms replace some of the hydroxyl groups in sucrose, a very sweet calorie-free sugar known as _______ is formed.
4. The compound inositol has six hydroxyl groups attached to a six-carbon backbone. Thus inositol can be classified as a(n)_______.
5. The reaction H —A— OH H — B— OH → H —A— B— OH + H2O represents a _______.
6. All amino acids have a hydrogen atom, an amino group, and a _______ group.
7. In proteins, amino acids are linked together by _______ bonds.
8. The linear arrangement of amino acids in the polypeptide chain is referred to as the _______ structure of the protein.
9. The covalent bond forces between the sulfur atoms of two cysteine side chains is called a _______.
10. van der Waals forces can form between _______ side chains in proteins.
11. Carbohydrates made up of two simple sugars are called _______.
12. All living cells contain the monosaccharide _______.
13. The bonds that link sugar monomers in a starch molecule are _______ bonds.
14. The highly branched polysaccharide that stores glucose in the muscle and the liver of animals is _______.
15. A(n) _______ linkage connects the fatty acid molecule to glycerol.
16. Fatty acids with more than one carbon–carbon double bond are called _______.
17. Fluidity and melting point of fatty acids are partially determined by the number of _______ bonds.
19. Vitamins D, E, and F have a multiple-ring structure and are members of a family of lipids known as _______.
20. The diversity found among DNA molecules is due to the sequence of _______.
18. Cholesterol is classified as a(n) _______.
1. The surface area-to-volume ratio of an object can be decreased by
2. What must cells do in order to survive?
a. Obtain and process energy
b. Convert genetic information into proteins
c. Keep certain biochemical reactions separate from one another
3. How does the surface area-to-volume ratio of a 1-mm cube compare to the surface area-to-volume ratio of a 3-mm cube?
d. The ratio decreases as the cube becomes larger.
4. What is the major distinction between a prokaryotic and a eukaryotic cell?
a. A prokaryotic cell does not have a nucleus, whereas a eukaryotic cell does.
5. Which of the following is not a characteristic of a prokaryotic cell?
b. A nuclear envelope
6. Members of the domains Bacteria and Archaea
d. are prokaryotes.
7. Which of the following is (are) found in prokaryotic cells?
8. A prokaryotic cell does not have a _______ or _______.
a. nucleus; organelles
9. You would not expect to find RNA in which of the following structures?
10. The DNA of prokaryotic cells is found in the
d. nucleoid region.
11. Ribosomes are not visible under a light microscope, but they can be seen with an electron microscope because
c. electron microscopes have more resolving power than light microscopes.
12. A general function of all cellular membranes is to
a. regulate which materials can cross the membrane.
13. The cytosol
c. is composed largely of water.
14. A specialized structure found in some prokaryotes is the
a. cell wall.
15. Specialized cellular appendages of prokaryotes that help bacteria adhere to one another when they exchange genetic material are called
a. carry on photosynthesis.
17. Some bacteria are able to propel themselves through liquid by means of a structure called the
18. If you removed the pili from a bacterial cell, which of the following would you expect to happen?
b. The bacterium would not adhere to other cells as well.
19. Why are prokaryotic cells generally smaller than eukaryotic cells?
e. Eukaryotes have compartmentalization, which allows for specialization.
20. The membrane surrounding each organelle
b. regulates traffic into and out of the cell.
21. Which statement about the nuclear envelope is true?
a. It contains pores for the passage of large molecules.
b. It is composed of two membranes.
22. The roles of biological membranes in eukaryotic cells include which of the functions listed below?
a. Separating a cell from its environment
b. Selecting what goes into and out of the cell
c. Maintaining a constant internal environment
d. Communicating with adjacent cells
23. A large organelle found in eukaryotic cells that genetically controls the cell’s activities is the
24. Of the following structures of an animal cell, the one with the largest volume is the
25. The membranes of the endoplasmic reticulum are continuous with the membranes of the
26. Plant and animal cells are similar in appearance. One difference is that
b. only animal cells contain centrioles.
27. Ribosomes are made up of
c. RNA and proteins.
28. Ribosomes are the structures in which
c. genetic information is used to make proteins.
29. Ribosomes are not found in
e. the Golgi apparatus.
30. Chromatin is a series of entangled threads composed of
b. DNA and protein.
31. Which of the following is not a component of the endomembrane system?
32. The rough ER is the portion of the ER that
c. has ribosomes attached to it.
33. Cholesterol is synthesized by
c. the SER.
34. An organelle consisting of a series of flattened sacks stacked somewhat like pancakes is the
c. Golgi apparatus.
35. Proteins that are transported in vesicles are made by
d. ribosomes on the rough endoplasmic reticulum.
36. Proteins from the Golgi are transported to the correct location by means of
a. signals found on the packaged proteins.
37. Lysosomes are important to eukaryotic cells because they contain
e. digestive enzymes.
38. Which of the following is true of lysosomes?
a. They are the sites where autophagy occurs.
39. In the mitochondria, “food” molecules are converted to ATP by a process known as
a. cellular respiration.
40. The DNA of mitochondria
b. is used to make proteins needed for cellular respiration.
41. What is the purpose of the folds of the inner mitochondrial membrane?
c. They increase the surface area for the exchange of substances across the membrane.
42. A secondary lysosome is a lysosome that
d. is a primary lysosome that has fused with a phagosome.
43. The DNA of a chloroplast is located in the
44. Components of chloroplasts include
a. grana and thylakoids.
45. Which type of organelle is found in plants but not in animals?
46. What is the difference between “free” and “attached” ribosomes?
a. Free ribosomes are in the cytoplasm, whereas attached ribosomes are anchored to the endoplasmic reticulum.
b. Free ribosomes produce proteins in the cytosol, whereas attached ribosomes produce proteins that are inserted into the ER.
47. The carotenoid pigments that give ripe tomatoes their red color are contained in organelles called
48. Which of the following is a function of a plant cell vacuole?
a. Storage of toxic by-products and wastes
b. Support for the cell
c. Containment of animal-attracting pigments that aid in pollination
d. Hydrolysis of seed proteins into plant embryo food
49. An organelle found only in plant cells is the
50. Chloroplasts are the structures in which
d. sunlight energy is converted into chemical energy.
51. Chloroplasts are a kind of
52. Of the following plant cell structures, which is most likely to have the greatest volume?
53. Starch molecules are stored inside
54. The overall shape of a cell is determined by its
55. Which of the following is not a function of vacuoles?
e. Helping to anchor the cell in place
56. Microtubules are composed of monomers of
a. a- and b-tubulin.
57. Which of the following structures is (are) involved with the movement of organelles within a cell?
58. Hair and intermediate filaments are composed of
59. Microtubules are made of
b. tubulin, and they are essential in chromosome distribution during mitosis.
60. An organelle with an internal cross-section showing a characteristic “9 + 2” morphology is the
a. are shorter and more numerous than flagella.
62. The surface area of the small intestine is greatly increased by
63. Microvilli are created by projections of
64. Which of the following organelles is found at the base of every eukaryotic cilium and flagellum?
b. Basal body
65. The cellular structures that are almost identical to centrioles are
a. basal bodies.
66. Which semirigid structure supports the plant cell and determines its shape?
67. Uniform concentrations of cytoplasmic materials in plants are maintained by
b. membrane-lined channels called plasmodesmata.
69. The extracellular matrix of animal cells
d. helps orient cell movements during embryonic development.
70. Some organelles in eukaryotic cells are thought to have
d. originated from endosymbiotic relationships.
71. Which of the following organelles were once independent prokaryote organisms?
b. Mitochondria and chloroplasts
72. Which of the following is not an argument for the endosymbiotic theory?
b. Mitochondria and chloroplasts cannot be grown in culture, free of a host cell.
1. The fundamental unit of life is the _______.
2. The three principle tenets of biology—that all organisms are composed of cells, that all cells come from preexisting cells, and that cells are the fundamental units of life—make up the unifying principle known as the _______.
3. When you cut an orange in half, you _______ the surface area-to-volume ratio.
4. The light microscope has glass lenses that focus visible light for imaging, whereas the electron microscope has _______ that focus electrons for imaging.
5. The ability of living organisms to maintain a constant internal environment is known as _______.
6. The DNA in a prokaryotic cell can be found in the _______ region.
7. Archaea and Bacteria do not typically have membrane-enclosed internal compartments; therefore they are known as _______.
8. Some bacteria are not detected by the human immune system because they possess an outer layer of slime known as _______.
9. Membrane-bound compartments with distinctive shapes and functions are termed _______.
10. RNA is able to carry information for protein synthesis from the DNA in the nucleus to the ribosomes in the cytoplasm by passing through small perforations in the nuclear membrane called _______.
11. The shape of the nucleus is maintained by a protein meshwork called the _______.
12. The _______ is an organelle that serves as a sort of “post office” where some of the proteins synthesized on ribosomes and rough ER are processed and sent to their destinations.
13. Steroids, fatty acids, and phospholipids are synthesized in the _______.
14. The side of the Golgi facing the ER is the _______ face.
15. The substances that enter the Golgi come from the _______.
16. The organelle with many folds called cristae is the _______.
17. _______ is the process by which light energy is converted into chemical bonds.
18. Toxic peroxides that are formed unavoidably as side products of important cellular reactions are collected and neutralized in _______.
20. Tough ropelike filaments that stabilize cell structure and resist tension are classified as an _______ type of filament.
1. The compounds in biological membranes that form a barrier to the movement of hydrophilic materials across the membrane are
2. Biological membranes are composed of
3. Which of the following statements about the proteins of the plasma membrane and the proteins of the inner mitochondrial membrane is true?
e. The two membranes differ in their lipid composition.
4. The plasma membrane of animals contains carbohydrates
b. on the outer side of the membrane, protruding into the environment.
5. In biological membranes, the phospholipids are arranged in a
a. bilayer, with the fatty acids pointing toward each other.
6. Cholesterol molecules act to
e. alter the fluidity of the membrane.
7. Peripheral membrane proteins have
e. polar regions that interact with similar regions of integral membrane proteins.
8. The functional roles for different proteins found in membranes include all except
e. stabilizing the lipid bilayer.
9. Houseplants adapted to indoor temperatures may die when accidentally left outdoors in the cold because their
b. membranes lack adequate fluidity.
10. A protein that forms an ion channel through a membrane is most likely to be
b. a transmembrane protein.
11. The hydrophilic regions of a membrane protein are most likely to be found
d. exposed on the surface of the membrane.
12. A characteristic of plasma membranes that helps them fuse during vesicle formation and phagocytosis is the
b. capacity of lipids to associate and maintain a bilayer organization.
13. The plasma membranes of winter wheat are able to remain fluid when it is extremely cold by
d. replacing saturated fatty acids with unsaturated fatty acids.
14. Which type of membrane protein would likely be most easily removed in a laboratory experiment?
c. Peripheral proteins
16. The LDL receptor is an integral protein that crosses the plasma membrane, with portions of the protein extending both outside and into the interior of the cell. The amino acid side chains (R groups) in the region of the protein that crosses the membrane are most likely
17. When a membrane is prepared by freeze-fracture and examined under the electron microscope, the exposed interior of the membrane bilayer appears to be covered with bumps. These bumps are
a. integral membrane proteins.
18. When vesicles from the Golgi apparatus deliver their contents to the exterior of the cell, they add their membranes to the plasma membrane. The plasma membrane does not increase in size, because
c. membrane is continually being lost from the plasma membrane by endocytosis.
19. Protein movement within a membrane may be restricted by
c. the cytoskeleton and lipid rafts.
20. Which of the following functions as a recognition signal for interactions between cells?
21. Which of the following represents the correct pathway for the synthesis and secretion of insulin, a protein secreted by the cells of the pancreas?
a. Rough ER; Golgi apparatus; vesicle; plasma membrane
22. Which of the following are not specialized cell junctions?
d. Cytoplasmic plaques
23. Muscle cells recognize and adhere to one another because of specific membrane proteins called
b. cell adhesion molecules.
24. Cell growth can involve movement of membrane material from
b. the Golgi apparatus to the cell membrane.
25. The difference between tight junctions, desmosomes, and gap junctions is that
c. tight junctions and desmosomes have mechanical roles, whereas gap junctions facilitate communication between cells.
26. Desmosomes include or associate with
a. dense plaque-like regions.
b. keratin fibers.
c. external cell adhesion molecules.
27. Structures that contain networks of keratin fibers and provide mechanical stability to epithelial tissues are called
28. The electric signal for a contraction passes rapidly from one muscle cell to the next by way of
c. gap junctions.
29. Specialized channel proteins called connexons occur in
e. gap junctions.
30. Which of the following statements about diffusion is false?
e. Simple diffusion depends upon specific carrier proteins.
31. Which of the following is an example of passive transport?
a. Facilitated diffusion
32. Which of the following does not affect the rate of diffusion of a substance?
d. Presence of other substances in the solution
33. A concentration gradient of glucose across a membrane means that
b. glucose molecules are more crowded on one side of the membrane than on the other.
34. When placed in water, wilted plants lose their limpness because of
c. osmosis of water into the plant cells.
35. The difference between osmosis and diffusion is that
d. osmosis refers to the movement of water, whereas diffusion is the movement of molecules.
36. If a shallow pan is filled with water, a drop of red ink is placed in one end of the pan, and a drop of green ink is placed in the other end, which of the following will be true at equilibrium?
b. The red and green inks will be uniformly distributed throughout the pan.
37. Osmosis is a specific form of
38. Osmosis moves water from a region of _______ to a region of _______.
b. low concentration of dissolved material; high concentration of dissolved material
39. Which of the following molecules is the most likely to diffuse across a cell membrane?
c. A steroid
40. When a severely dehydrated patient is brought to the hospital, an IV of normal saline is started immediately. Distilled water is not used because
c. it would cause blood cells to swell and eventually burst.
41. When placed in a hypertonic solution, animal cells
a. helps cells maintain turgor pressure in plants.
43. If a red blood cell is placed in an isotonic solution,
e. water moves into and out of the cell at an equal rate.
44. The speed and direction of ions as they move into and out of the cell are determined by the
b. concentration gradient and electrochemical imbalances.
45. Which of the following statements about channel proteins is true?
a. They have a central pore of polar amino acids and water.
b. They are anchored in the hydrophobic bilayer of the plasma membrane.
c. They are surrounded by nonpolar amino acids.
d. They are usually gated.
46. One result of the movement of ions through ion channels is the creation of a membrane potential.
The membrane potential is
a. a charge imbalance across the plasma membrane.
47. How does an ion channel exert its specificity for one ion and not another?
e. The ion lets go of its water and is attracted to a channel pore protein.
48. Water crosses the plasma membrane at a rate faster than expected due to
a. hydration of the ions as they pass through.
b. water channels called aquaporins.
50. In facilitated diffusion, the diffusion rate of a specific molecule across a membrane does not continue to increase as the concentration difference of the molecule across the membrane increases because
c. the carrier proteins are saturated.
51. Active transport usually moves molecules
b. in the opposite direction in which diffusion moves them.
52. Secondary active transport involves all of the following except
a. the direct use of ATP.
53. Amino acids enter cells against their concentration gradients by means of
d. secondary active transport.
54. In the intestine, Na+ and an amino acid bind to the same transport protein that moves the two substances in the same direction. This type of active transport is called
a. a symport.
55. Plant cells transport sucrose across the vacuole membrane against its concentration gradient by a process known as
b. a symport.
56. In the parietal cells of the stomach, the uptake of chloride ions is coupled to the transport of bicarbonate ions out of the cell. This type of transport system is called
e. an antiport.
57. The only process that can bring glucose molecules into cells and does not involve the metabolic energy of ATP is
58. For each molecule of ATP consumed during active transport of sodium and potassium,
d. two K+ ions are imported and three Na+ ions are exported.
59. Receptor-mediated endocytosis is the mechanism for transport of
60. Phagocytosis, pinocytosis, and receptor-mediated endocytosis all involve
b. invagination of the plasma membrane.
61. Which of the following processes does not involve the uptake of materials into the cell?
62. Persons with the inherited disease familial hypercholesterolemia have very high levels of cholesterol because of
c. deficient LDL receptor proteins.
63. Which of the following is not a function of plasma membranes?
a. Conversion of glucose energy to ATP
b. Arrangement of enzymes
c. Turning off of a specific cell functiond. Conduction of nerve impulses
64. An important function of specialized membranes found in certain organelles is to
c. transform energy.
1. The study of the spread and control of disease is called _______.
2. Most of the lipids composing biological membranes are called _______.
3. Biological membranes are composed of a continuous phospholipid bilayer in which proteins are embedded. This general design is known as the _______ model.
4. Lipids can move _______, however, they seldom move across the bilayers of a biological membrane.
5. Membrane proteins covalently bonded to carbohydrates are called _______.
6. Membrane lipids covalently bonded to carbohydrates are called _______.
7. Membrane segments synthesized on the ER move to other points of the cell as _______.
8. Cell adhesion molecules of the same type are called _______.
9. Cell adhesion molecules that are responsible for mammalian egg and sperm cells binding to one another are referred to as _______.
10. The cells of the intestinal epithelium are linked together in order to prevent substances from passing between them. The type of cell junction linking these cells is called a _______.
11. The processes of cell recognition and cell adhesion are dependent upon _______ proteins.
12. _______ is the process of random movement toward a state of equilibrium.
13. The ability of some materials to move through biological membranes more readily than through others is called _______.
14. Diffusion is the net movement of particles from regions of _______ concentration to regions of _______ concentration.
15. If a cell placed within a solution shrinks, the solution is _______ relative to the cell.
16. When plant cells are placed in a hypotonic solution, water enters the cells and exerts pressure against the cell wall. This force is called _______ pressure.
17. The coupled transport system by which glucose and sodium ions simultaneously enter intestinal epithelial cells is called _______.
18. The sodium–potassium pump of cell membranes is an example of a coupled transport called a(n) _______.
19. _______ involves coated pits, clathrin, and coated vesicles.
20. The process by which the plasma membrane engulfs large particles or even whole cells is called _______.
1. The sum total of all the chemical reactions in a living structure is called its
2. Water held back by a dam represents what kind of energy?
3. Which of the following represents potential energy?
a. Chemical bonds
b. Concentration gradient
c. Electric charge imbalance
4. What can never be created or destroyed?
5. During photosynthesis, plants use light energy to synthesize glucose from carbon dioxide. However, plants do not use up energy during photosynthesis; they merely convert it from light energy to chemical energy. This process is an illustration of
c. the first law of thermodynamics.
6. The first law of thermodynamics states that the total energy in the universe is
7. In any system, the total energy includes usable and unusable energy. The unusable energy is a measure of the disorder of the system and is referred to as
8. A change in free energy is related to a change in
a. temperature.b. entropy
9. If DG of a chemical reaction is negative and the change in entropy is positive, you can conclude that the reaction
c. is exergonic.
10. The standard free energy change for the hydrolysis of ATP to ADP + Pi is –7.3 kcal/mol. From this information one can conclude that
e. the reaction is exergonic.
11. Which of the following statements about the exergonic hydrolysis of maltose to glucose is true?
d. The reaction releases free energy.
12. Chemical equilibrium
e. is a state in which DG = 0.
13. When ADP gains a phosphate to form ATP,
b. energy is consumed.
14. How does the second law of thermodynamics apply to organisms?
b. To maintain order, life requires a constant input of energy.
16. ATP can phosphorylate many different molecules. This means that ATP can
b. donate phosphate groups.
17. A readily reversible reaction, in which reactants and products have almost the same free energies, is indicated by a
d. DG near zero.
18. Phosphorylation of ADP to ATP is endergonic, whereas the hydrolysis of ATP to ADP is exergonic. The two reactions are therefore said to be
19. In glycolysis, the exergonic reaction 1,3-diphosphoglycerate ® 3-phosphoglycerate is coupled to the reaction ADP + Pi ® ATP. Which of the following is most likely to be true about the reaction ADP + Pi ® ATP?
d. The reaction is endergonic.
c. use ATP to begin luciferin oxidation.
21. Which of the following statements about ATP is true?
e. On average, ATP is consumed within one second of its formation.
22. An RNA molecule that has enzyme activity is called
e. a ribozyme.
23. The rate of a chemical reaction in a cell is the measure of how
b. quickly the reaction reaches equilibrium.
24. Knowing the change in free energy (DG) of a reaction tells us
a. the equilibrium point of the reaction.
25. Which of the following is an example of an exergonic reaction?
b. Cellular respiration
26. Which of the following statements about enzymes is false?
e. Most enzymes are much smaller than their substrates.
27. What is a transition state?
d. The state at which the bonds of reactants are unstable
28. The presence of a catalyst affects the
e. free energy of the transition state.
29. Which of the following determines the rate of a reaction?
d. The activation energy
30. In a chemical reaction, transition-state species have free energies that are
b. higher than either the reactants or the products.
31. The hydrolysis of sucrose to glucose and fructose is exergonic. However, if sucrose is dissolved in water and the solution is kept overnight at room temperature, there is no detectable conversion to glucose and fructose. Why?
b. The activation energy of the reaction is high.
32. Trypsin and elastase are both enzymes that catalyze hydrolysis of peptide bonds. But trypsin only cuts next to lysine and elastase only cuts next to alanine. Why?
c. The shape of the active site for the two enzymes is different.
33. The statement “enzymes are highly specific” means that certain
b. reactions involving certain substrates are catalyzed by specific enzymes.
34. An active site is
b. the part of the enzyme that binds with a substrate.
35. In some cases, a substrate–enzyme complex is stabilized by
a. hydrogen bonds.
b. covalent bonds.
c. ionic attractions.
d. hydrophobic interactions.
36. The molecules that are acted on by an enzyme are called
37. The enzyme sucrase increases the rate at which sucrose is broken down into glucose and fructose. Sucrase works by
b. lowering the activation energy of the reaction.
38. Which of the following statements about enzymes is true?
a. Enzymes are proteins.
b. Enzymes have a specific amino acid sequence.
c. Enzymes are highly specific.
d. Enzymes lower the energy barrier.
39. The enzyme a-amylase increases the rate at which starch is broken down into smaller oligosaccharides by _______ of the reaction.
e. lowering the activation energy
40. The enzyme glyceraldehyde 3-phosphate dehydrogenase catalyzes the reaction glyceraldehyde 3-phosphate ® 1,3-diphosphoglycerate. The binding of the glyceraldehyde 3-phosphate to the enzyme creates a(n)
d. enzyme–substrate complex.
41. The enzyme glucose oxidase binds the six-carbon sugar glucose and catalyzes its conversion to glucono-1,4-actone. Mannose is also a six-carbon sugar, but glucose oxidase cannot bind mannose. The specificity of glucose oxidase is based on the
d. three-dimensional shape and structure of the active site.
42. Binding of substrate to the active site of an enzyme is
43. Which of the following is an enzyme?
44. Enzymes of the acid–base catalysis type contain
d. acidic or basic amino acid side chains (R group) in the active site.
45. The catalysis mechanism used by lysozyme to breakdown bacterial cell walls is
d. induced strain.
46. Enzymes catalyze a reaction by _______ the substrates.
e. enzyme retrofit.
a. All of the alcohol dehydrogenase molecules are bound to acetaldehyde molecules.
47. The ability of an enzyme to change shape when it binds to its substrate is called
a. induced fit.
49. Many enzymes require ATP and ADP for a reaction to occur. They temporarily bind to and then release from the substrate to participate in other reactions. ATP and ADP are considered
50. Enzymatic reactions can become saturated as substrate concentration increases because
e. there are a limited number of the enzyme molecules present.
51. Competitive inhibitors of enzymes work by
a. fitting into the active site.
52. Nerve gases such as Sarin and malathion
a. block specific chemical transformations by inactivating specific enzymes.
53. How do competitive and noncompetitive enzyme inhibitors differ?
a. Competitive inhibitors bind to the active site, whereas noncompetitive inhibitors change the shape of the active site.
54. Enzymes are sensitive to
c. irreversible inhibitors such as DIPF.
d. allosteric effectors.
55. The addition of the competitive inhibitor mevinolin slows the reaction HMG-CoA ® mevalonate, which is catalyzed by the enzyme HMG-CoA reductase. The effects of mevinolin would be overcome and the rate of the reaction increased by
b. adding more HMG-CoA.
56. A noncompetitive inhibitor inhibits binding of a substrate to an enzyme by
e. changing the shape of the active site.
57. Which type of inhibitor can be overcome completely by the addition of more substrate?
58. An allosteric inhibitor
b. changes the shape of an enzyme.
59. Allosteric inhibitors act by
d. decreasing the amount of the active form of the enzyme.
60. The inhibition of enzyme activity by noncompetitive inhibitors can be reduced
e. only when they become unbound.
61. The maximum possible rate of an enzyme reaction that is influenced by a competitive inhibitor depends on the concentration of
62. Negative feedback in a sequence of chemical reactions involves a chemical that appears _______ in the sequence and _______ reaction.
a. late; inhibits an earlier
63. The process that involves an end product acting as an inhibitor of an earlier step in a metabolic pathway is called
b. feedback inhibition.
64. Which of the following statements about allosteric regulators is true?
a. The plot for allosteroic regulators often has a sigmoid curve.
65. Enzymes are highly sensitive to pH and temperature because
c. of their three-dimensional structure and side chains.
66. Environmental conditions that affect enzyme function include
67. Denatured enzymes are the same as
d. enzymes that can no longer function.
68. End products of biosynthetic pathways often act to block the initial step in that pathway. This phenomenon is called
d. feedback inhibition.
69. Which of the following is a group of enzymes that are important in allowing organisms to adapt to changes in their environment?
c. Allosteric enzymes
70. If the temperature of an enzyme-catalyzed reaction is increased from 40°C to 70°C, the rate of the reaction
e. cannot be determined without information regarding optimal temperature.
71. When organisms move from one environment to another, they sometimes synthesize variations of existing enzymes, which are called
1. Cells cannot create energy because _______ cannot be created or destroyed.
2. The capacity to do work is known as _______.
3. Heat, light, electricity, and motion are all examples of _______ energy.
4. The energy in a system that exists due to position is called _______ energy.
5. Potential energy can be converted into _______ energy, which does work.
6. The building up of molecules in a living system is known as _______; the breaking down of molecules in a living system is known as _______.
7. The first law of thermodynamics states that _______ is neither created nor destroyed.
8. The second law of thermodynamics states that the _______, or disorder, of the universe is constantly increasing.
9. When a drop of ink is added to a beaker of water, the dye molecules become randomly dispersed throughout the water. This is an example of an increase in _______.
10. If the DG of a spontaneous reaction is negative, indicating that the reaction releases free energy, the reaction is _______.
11. Cells mostly use _______ as an immediate source of energy to drive reactions.
12. Enzymes are biological _______.
13. The amount of energy needed to start a reaction is known as the _______ energy.
14. The enzyme phosphoglucoisomerase catalyzes the conversion of glucose 6-phosphate to fructose 6-phosphate. The region on phosphoglucoisomerase where glucose 6-phosphate binds is called the _______.
15. A change in enzyme shape caused by substrate binding is called _______.
16. Although some enzymes consist entirely of one or more polypeptide chains, others possess a permanently bound nonprotein portion called a(n) _______.
17. Zinc ions that bind to enzymes are called _______.
18. The chemical activities of a living organism are organized into _______ in which the product of one reaction is the reactant for the next reaction.
19. When an enzyme is heated until its three-dimensional structure is destroyed, the enzyme is said to be _______.
20. Variations of enzymes that allow organisms to adapt to changing environments are termed _______.
a. a short-term energy-storagecompound.
b. the cell’s principalcompound for energy transfers.
c. synthesized withinmitochondria.
d. the molecule all living cellsrely on to do work.
2. Which of the followingstatements about metabolic pathways is false?
c. Almost all are anabolic.
3. Which of the followingstatements about metabolic pathways is true?
e. Each one is regulated byspecific enzymes.
4. When a molecule loseshydrogen atoms (as opposed to hydrogen ions), it becomes
5. In the conversion ofsuccinate to fumarate, hydrogen atoms are transferred to FAD. The conversion ofsuccinate and FAD to fumarate and FADH2 is an example of
e. a redox reaction.
6. The oxidation of malate tooxaloacetate is coupled to the reduction of NAD+ to NADH + H+.NAD+ is a(n)
b. oxidizing agent.
7. Which of the followingprocesses occurs when oxygen is unavailable?
8. In all cells, glucosemetabolism begins with
9. When NADH donates twoelectrons to ubiquinone during respiration, ubiquinone is
10. The end product of glycolysisis
b. the starting point forpyruvate oxidation.
c. the starting point for thefermentation pathway.
11. Which of the followingoxidizes other compounds by gaining free energy and hydrogen atoms and reducesother compounds by giving up free energy and hydrogen atoms?
12. The function of NAD+is to
c. carry hydrogen atoms andfree energy from compounds being oxidized and to give hydrogen atoms and freeenergy to compounds being reduced.
a. is a key electron carrierin redox reactions.
14. In the cell, the site ofoxygen utilization is the
15. In the first reaction ofglycolysis, glucose receives a phosphate group from ATP. This reaction is
16. During the energy-primingportion of glycolysis, the phosphates from ATP molecules are
a. added to the first andsixth carbons.
17. In order for glucose to beused as an energy source, it is necessary that
d. two ATP molecules beinvested in the system.
18. ATP is used to drive thefirst five reactions of glycolysis because
b. the breakdown of ATP to ADPis exergonic.
19. The first five reactionsof the glycolytic pathway result in
a. the addition of phosphates,modification of sugars, and formation of G3P.
20. The free energy releasedduring the oxidation of glyceraldehyde 3-phosphate to 1,3-bisphosphoglycerateis
d. used to reduce NAD+.
21. The end result ofglycolysis is the
c. formation of 2 molecules ofpyruvate.
22. Within the cell, thepyruvate dehydrogenase complex, a multi-enzyme complex of the citric acidcycle, is located in the
d. mitochondrial membrane.
23. Pyruvate oxidationgenerates
b. NADH + H+ from NAD+.
c. a change in free energy.
d. a capture of energy.
24. In steps 6 through 10 ofglycolysis, the conversion of one mole of glyceraldehyde 3-phosphate topyruvate yields 2 moles of ATP. But the oxidation of glucose to pyruvateproduces a total of 4 moles of ATP. Where do the remaining 2 moles of ATP comefrom?
a. One mole of glucose yields2 moles of glyceraldehyde 3-phosphate.
25. Substrate-levelphosphorylation is the transfer of a(n)
c. phosphate to an ADP.
26. Some of the free energyreleased by oxidation of pyruvate to acetate is stored in acetyl CoA. How doesacetyl CoA store free energy?
a. Acetyl CoA has a higherfree energy than acetate.
27. During the citric acidcycle, energy stored in acetyl CoA is used to
d. drive the reactionoxaloacetate ®citric acid.
28. Which of the following isproduced during the citric acid cycle?
c. Reduced electron carriers
29. The citric acid cyclebegins with
c. acetyl CoA.
30. During the citric acidcycle, oxidative steps are coupled to
e. the reduction of electroncarriers.
31. For the citric acid cycleto proceed, it is necessary for
c. an acetyl group to bind tooxaloacetate.
32. How does the reduction ofpyruvate to lactic acid during fermentation allow glycolysis to continue in theabsence of oxygen?
c. This reaction is coupled tothe oxidation of NADH to NAD+.
33. The formation of ethanolfrom pyruvate is an example of
c. a fermentation process thattakes place in the absence of oxygen.
34. Regardless of the electronor hydrogen acceptor employed, fermentation always produces
35. During glycolysis, foreach mole of glucose oxidized to pyruvate,
c. 4 moles of ATP areproduced.
36. Animals breathe in aircontaining oxygen and breathe out air with less oxygen and more carbon dioxide.The carbon dioxide comes from
b. the citric acid cycle.
37. For glycolysis tocontinue, all cells require
38. In the absence of oxygen,cells capable of fermentation
e. oxidize NADH to produce NAD+.
39. For bacteria to continuegrowing rapidly when they are shifted from an environment containing oxygen toan anaerobic environment, they must
e. increase the rate of theglycolytic reactions.
40. More free energy isreleased during the citric acid cycle than during glycolysis, but only 1 moleof ATP is produced for each mole of acetyl CoA that enters the cycle. Most ofthe remaining free energy that is produced during the citric acid cycle is
b. used to reduce electroncarriers.
41. In human muscle cells, thefermentation process produces
a. lactic acid.
42. The oxidation of pyruvateto carbon dioxide is called
b. the citric acid cycle.
43. In alcoholic fermentation,NAD+ is produced during the
c. reduction of acetaldehydeto ethanol.
44. During the fermentation ofone molecule of glucose, the net production of ATP is _______ molecule(s).
45. Many species derive theirenergy from fermentation. The function of fermentation is to
c. oxidize NADH + H+,ensuring a continued supply of ATP.
46. Yeast cells tend to createanaerobic conditions because they use oxygen more quickly than it can bereplaced by diffusion through the cell membrane. For this reason, yeast cells
d. produce ethanol.
47. The oxidizing agent at theend of the electron transport chain is
48. Which of the followingevents occurs in the electron transport chain?
c. Cytochromes, FADH, and NADHare oxidized.
49. The electron transportchain contains four large protein complexes (I, II, III, and IV), cytochrome c,and ubiquinone. The function of these molecules is to
a. transport electrons.
50. Oxygen is used by
51. Which of the followingstatements about the electron transport chain is true?
a. Electrons are received fromNADH and FADH2.
b. Electrons are passed fromdonor to recipient carrier molecules in a series of oxidation-reductionreactions.
c. Usually the terminalelectron acceptor is oxygen.
d. Most of the enzymes arepart of the inner mitochondrial membrane.
52. The electron transportchain contains four large protein complexes: NADH-Q reductase complex,succinate dehydrogenase, cytochrome c reductase complex, and cytochrome c oxidasecomplex. These proteins
a. are integral proteins.
53. Animals inhale aircontaining oxygen and exhale air with less oxygen and more carbon dioxide.After inhalation, the extra oxygen from the air will mostly be found in
54. The drug 2,4-dinitrophenol(DNP) destroys the proton gradient across the inner mitochondrial membrane.What would be the effect of incubating isolated mitochondria in a solution ofDNP?
b. No ATP would be made duringtransport of electrons down the respiratory chain.
55. Electron transport withinNADH-Q reductase, cytochrome reductase, and cytochrome oxidase can be coupledto proton transport from the mitochondrial matrix to the space between theinner and outer mitochondrial membranes, because those protein complexes are
b. within the innermitochondrial membrane.
56. Water is a by-product ofcellular respiration. The water is produced as a result of the
d. reduction of oxygen at theend of the electron transport chain.
57. According to thechemiosmotic theory, the energy for the synthesis of ATP during the flow ofelectrons down the respiratory chain is provided directly by the
c. diffusion of protons.
58. The proton-motive force is
b. the proton concentrationgradient and electric charge difference.
59. The chemiosmoticgeneration of ATP is driven by
d. a difference in H+concentration on both sides of a membrane.
60. The hydrogen ion gradientis maintained by
a. electron transport andproton pumping.
61. When hydrogen ions arepumped from the mitochondrial matrix across the inner membrane into theintermembraneous space, the result is the
c. creation of a protongradient.
62. The chemiosmoticgeneration of ATP is driven by
d. the proton-motive force.
63. The component of aerobicrespiration that produces the most ATP per mole of glucose is
a. the electron transportchain.
64. In some mammals, such asnew born humans and hibernating animals, body temperature is raised by means of
a. the uncoupling ofrespiration by the protein thermogenin.
65. Most ATP produced in ourbodies is made
c. using ATP synthase.
66. Which process convertsglucose to pyruvate, generating a small amount of ATP but no carbon dioxide?
67. Before starch can be usedfor respiratory ATP production, it must be hydrolyzed to
68. When yeast cells areswitched from aerobic to anaerobic growth conditions, the rate of glycolysisincreases. The rate of glycolysis is regulated by the concentration of _______in the cells.
69. When acetyl CoA builds upin the cell, it increases the activity of the enzyme that synthesizesoxaloacetate from pyruvate and carbon dioxide. Acetyl CoA is acting as a(n)
c. allosteric activator.
70. When a cell needs energy,cellular respiration is regulated by isocitrate dehydrogenase, an enzyme of thecitric acid cycle. This enzyme is stimulated by
71. The main control mechanismin glycolysis is the
d. the enzymephosphofructokinase.
72. In yeast, if the citricacid cycle is shut down because of a lack of oxygen, glycolysis will probably
73. When the supply of acetylCoA being produced exceeds the demands of the citric acid cycle, some of theacetyl CoA is diverted to the synthesis of
d. fatty acids.
74. If a cell has an abundantsupply of ATP, acetyl CoA may be used
c. for fatty acid synthesis.
1. Muscle cells of marathonracers contain many mitochondria and use oxygen to break down fats andcarbohydrates. Ninety percent of marathon runners’ muscle is made up of_______.
2. In nonphotosyntheticorganisms, the most common chemical fuel is _______.
3. Oxidation and _______ occurtogether.
4. A chemical reaction resultingin the transfer of electrons or hydrogen atoms is called a _______ reaction.
5. Fermentation occurs in theabsence of oxygen and is therefore termed _______.
6. The loss of an electron bya ferrous ion (Fe2+) to yield a ferric ion (Fe3+) iscalled _______.
7. Due to its ability to carryelectrons and free energy, _______ is the most common electron carrier incells.
8. The abbreviation fornicotinamide adenine dinucleotide is _______.
9. In a redox reaction, thereactant that becomes oxidized is called a _______.