EXAM 2
Which component is cholesterol? A) A B) B C) C D) D E) E
E) E
Which component is the fiber of the extracellular matrix?
Answer: A
Which component is a glycolipid?
B
68. In what way do the membranes of a eukaryotic cell vary? a. Phospholipids are found only in certain membranes. b. Certain proteins are unique to each membrane. c. Only certain membranes of the cell are selectively permeable. d. Only certain membranes are constructed from amphipathic molecules. e. Some membranes have hydrophobic surfaces exposed to the cytoplasm, while others have hydrophilic surfaces facing the cytoplasm.
B) Certain proteins are unique to each membrane.
69. Based on the figure above, which of these experimental treatments would increase the rate of sucrose transport into the cell? a. decreasing extracellular sucrose concentration b. decreasing extracellular pH c. decreasing cytoplasmic pH d. adding an inhibitor that blocks the regeneration of ATP e. adding a substance that makes the membrane more permeable to hydrogen ions
B) decreasing extracellular pH
6. Refer to Nakano's quote from Science. If the cytosine is positively charged (+) before self-cleavage, what would its charge be after self-cleavage? a. + (positive) b. - (negative) c. 0 (neutral) d. no way to predict
B. -(negative)
1. What is the difference between a ribonucleotide and a deoxyribonucleotide? a. Ribonucleotides contain a phosphate group. b. Ribonucleotides have a hydroxyl group on the 2 carbon of their sugar subunit. c. Ribonucleotides contain a sugar with five carbon atoms. d. Ribonucleotides have a hydrogen atom on the 1 carbon of their sugar subunit.
B.)Ribonucleotides have a hydroxyl group on the 2 carbon of their sugar subunit.
Which component is a microfilament of the cytoskeleton?
C
65. For a protein to be an integral membrane protein, it would have to be _____. a. hydrophilic b. hydrophobic c. amphipathic, with at least one hydrophobic region d. completely covered with phospholipids e. exposed on only one surface of the membrane
C) amphipathic, with at least one hydrophobic region.
1. Explain how Chargaff's rules relate to the complementary base pairing seen in the secondary structure of DNA. Would you expect these rules to apply to RNA as well? Explain why or why not
Chargaff's Rule simply states that adenine base pairs with thymine, and that guanine base pairs with cytosine What this means is that the amount of adenine is equal to thymine, and the amount of guanine is equal to cytosine All organisms use DNA, so yes, chargaff's rule applies to all organisms.
71. Which of the following is most likely true of a protein that cotransports glucose and sodium ions into the intestinal cells of an animal? a. Sodium and glucose compete for the same binding site in the cotransporter. b. Glucose entering the cell down its concentration gradient provides energy for uptake of sodium ions against the electrochemical gradient. c. Sodium ions can move down their electrochemical gradient through the cotransporter whether or not glucose is present outside the cell. d. A substance that blocks sodium ions from binding to the cotransport protein will also block the transport of glucose.
D) A substance that blocks sodium ions from binding to the cotransport protein will also block the transport of glucose.
34. Cellulose is _____. a. a polymer composed of fructose monomers b. a storage polysaccharide for energy in plant cells c. used by plants to make glycogen d. a major structural component of plant cell walls e. a monomer of starch.
D. a major structural component of plant cell walls
2. What is/are the variable structure(s) of a nucleotide? a. the phosphate group b. the sugar c. the base d. the sugar and the base
D.)the sugar and the base
66. Glucose diffuses slowly through artificial phospholipid bilayers. The cells lining the small intestine, however, rapidly move large quantities of glucose from the glucose-rich food into their glucose-poor cytoplasm. Using this information, which transport mechanism is most probably functioning in the intestinal cells? a. simple diffusion b. phagocytosis c. active transport pumps d. exocytosis e. facilitated diffusion
E) facilitated diffusion
11. If cells are grown in a medium containing radioactive 32P-labeled phosphate, which of these molecules will be labeled? a. proteins b. cellulose c. amino acids d. nucleic acids e. glucose
E. Glucose
4. Some viruses consist only of a protein coat surrounding a nucleic acid core. If you wanted to radioactively label the nucleic acids separately from the protein, you would use radioactive _____. a. sulfur b. carbon c. nitrogen d. phosphorus
PHOSPHORUS
3. When nucleotides polymerize to form a nucleic acid _____. a. a covalent bond forms between the sugar of one nucleotide and the phosphate of a second b. a hydrogen bond forms between the sugar of one nucleotide and the phosphate of a second c. covalent bonds form between the bases of two nucleotides d. hydrogen bonds form between the bases of two nucleotides
a covalent bond forms between the sugar of one nucleotide and the phosphate of a second
23. Compare proteins to nucleic acids. Which of the following is true? a. Both have primary and secondary structure. b. Both contain sulfur. c. Both take on structural roles in the cell. d. Both have monomers, which contain phosphorus.
a. Both have primary and secondary structure.
40. Compare the molecular formula of a carbohydrate (CH2O)n with that of carbon dioxide (CO2). What does the presence of hydrogen atoms in carbohydrates indicate? a. Carbohydrates are more reduced than carbon dioxide. b. Carbohydrates are more oxidized than carbon dioxide. c. Every carbon atom in a carbohydrate is bonded to four different atoms. d. Carbohydrates contain a carbonyl functional group.
a. Carbohydrates are more reduced than carbon dioxide.
84. Centrioles, cilia, flagella, and basal bodies have remarkably similar structural elements and arrangements. Which of the following hypotheses is most plausible in light of such structural similarities? a. Cilia and flagella arise from centrioles. b. Loss of basal bodies should prevent cells from dividing in two. c. Motor proteins such as dynein must have evolved before any of these four kinds of structure. d. Cilia and flagella evolved separately in the same ancestral eukaryotic organism. e. Natural selection for cell motility repeatedly selected for microtubular arrays in circular patterns in the evolution of each of these structures.
a. Cilia and flagella arise from centrioles.
22. DNA is the main hereditary material of all life. However, DNA lacks one important characteristic for the first forms of life. Why have researchers rejected the idea that DNA was found in the first life form? a. It does not function as a catalyst. b. It is not stable enough to have withstood early Earth's harsh atmosphere. c. DNA only has four types of bases. Therefore, DNA cannot adapt and evolve. d. The type of sugar found in DNA is too complicated to have been present early in earths history
a. It does not function as a catalyst.
56. What is the most important factor in explaining why osmosis occurs spontaneously? a. It leads to an increase in entropy. b. It leads to a decrease in entropy. c. The process is exothermic. d. The process is endothermic
a. It leads to an increase in entropy.
12. DNA double helices are soluble in water but insoluble in alcohol. How do these physical properties reflect the chemical structure of the DNA molecule? a. The charged phosphate groups and sugars of DNA are hydrophilic. b. The purine and pyrimidine bases are hydrophilic. c. The 5-prime to 3-prime-polarity of DNA makes it soluble in water but not in alcohol. d. The charged R-groups of DNA are hydrophilic.
a. The charged phosphate groups and sugars of DNA are hydrophilic.
39. Enzymes that readily break starch apart cannot hydrolyze the glycosidic linkages found in cellulose. Why is this logical? a. The geometry of the bonds is different, and the shapes of enzyme active sites are highly specific. b. Starch is held together by hydrogen bonding, not covalent bonding. c. Cellulose molecules are highly branched, and enzymes are too bulky to fit. d. Starch is held together by peptide bonds, not glycosidic linkages.
a. The geometry of the bonds is different, and the shapes of enzyme active sites are highly specific.
26. The molecule shown in the accompanying figure is _____. a. a hexose b. a pentose c. a phosphate d. fructose e. maltose
a. a hexose
89. Spherocytosis is a human blood disorder associated with a defective cytoskeletal protein in the red blood cells (RBCs). What do you suspect is the consequence of such a defect? a. abnormally shaped RBCs b. an insufficient supply of ATP in the RBCs c. an insufficient supply of oxygen-transporting proteins in the RBCs d. adherence of RBCs to blood vessel walls, causing plaque formation
a. abnormally shaped RBCs
33. Starch and cellulose _____. a. are polymers of glucose b. are cis-trans isomers of each other c. can be digested by humans d. are used for energy storage in plants e. are structural components of the plant cell wall
a. are polymers of glucose
49. Cooking oil and gasoline (a hydrocarbon) are not amphipathic molecules because they _____. a. do not have a polar or charged region b. do not have a nonpolar region c. have hydrophobic and hydrophilic regions d. are highly reduced molecules
a. do not have a polar or charged region
50. The presence of cholesterol in the plasma membranes of some animal cells _____. a. enables the membranes to stay fluid when cell temperature drops b. enables the cell to remove hydrogen atoms from saturated phospholipids c. enables the cell to add hydrogen atoms to unsaturated phospholipids d. makes the cell membrane less flexible, allowing it to sustain greater intracellular pressure
a. enables the membranes to stay fluid when cell temperature drops
74. The evolution of eukaryotic cells most likely involved _____. a. endosymbiosis of an aerobic bacterium in a larger host cell—the endosymbiont evolved into mitochondria b. anaerobic archaea taking up residence inside a larger bacterial host cell to escape toxic oxygen—the anaerobic bacterium evolved into chloroplasts c. an endosymbiotic fungal cell evalving into the nucleus d. acquisition of an endomembrane system and subsequent evolution of mitochondria from a portion of the Golgi
a. endosymbiosis of an aerobic bacterium in a larger host cell—the endosymbiont evolved into mitochondria
35. Which of the following is NOT a polymer? a. glucose b. starch c. cellulose d. chitin e. DNA
a. glucose
44. Humans can digest starch but not cellulose because _____. a. humans have enzymes that can hydrolyze the α-glycosidic linkages of starch but not the β-glycosidic linkages of cellulose b. humans have enzymes that can hydrolyze the β-glycosidic linkages of starch but not the α-glycosidic linkages of cellulose c. starch monomers are joined by covalent bonds and cellulose monomers are joined by ionic bonds d. the monomer of starch is glucose, while the monomer of cellulose is galactose
a. humans have enzymes that can hydrolyze the α-glycosidic linkages of starch but not the β-glycosidic linkages of cellulose
54. The membranes of winter wheat are able to remain fluid when it is extremely cold by _____. a. increasing the percentage of unsaturated phospholipids in the membrane b. increasing the percentage of cholesterol molecules in the membrane c. decreasing the number of hydrophobic proteins in the membrane d. cotransport of glucose and hydrogen
a. increasing the percentage of unsaturated phospholipids in the membrane
32. All of the following are polysaccharides EXCEPT _____. a. lactose b. glycogen c. chitin d. cellulose e. amylopectin
a. lactose
55. The text states that ribonucleotides can diffuse through some types of liposomes. It is likely that the lipids present early in chemical evolution had short chains. Would liposomes formed from these types of lipids be more or less permeable to ribonucleotides than if early cells formed from long-chained lipids? a. more permeable b. less permeable c. same permeability
a. more permeable
43. Different organisms uses cell walls for protection from their environment and structural support. These cell walls must obviously be insoluble in water; otherwise, they would dissolve the first time an organism got wet. Which of the following carbohydrates would you expect to be most soluble in water? a. starch b. peptidoglycan c. cellulose d. chitin
a. starch
61. Which line or lines in the graph represent(s) bags that contain a solution that is hypertonic at 50 minutes? a. A and B b. B c. C d. D e. D and E
b. B
16. A double-stranded DNA molecule contains a total of 120 purines and 120-pyrimidine. This DNA molecule could be composed of _____. a. 120 adenine and 120 uracil molecules b. 120 thymine and 120 adenine molecules c. 120 cytosine and 120 thymine molecules d. 120 adenine and 120 cytosine molecules e. 120 guanine and 120 thymine molecules
b. 120 thymine and 120 adenine molecules
25. Glucose (C6H12O6) has a single carbonyl group (-C=O) in its linear form. Based on the number of oxygen atoms in glucose, how many hydroxyl groups (-OH) would you expect glucose to have? a. 6 b. 5 c. 3 d. 1
b. 5
17. If one strand of a DNA molecule has the sequence of bases 5'ATTGCA3', the other complementary strand would have the sequence _____. a. 5'TAACGT3' b. 5'TGCAAT3' c. 5'UAACGU3' d. 3'UAACGU5' e. 5'UGCAAU3'
b. 5'TGCAAT3'
31. The molecular formula for glucose is C6H12O6. What would be the molecular formula for a molecule made by linking three glucose molecules together by dehydration reactions? a. C18H36O18 b. C18H32O16 c. C6H10O5 d. C18H30O15 e. C3H6O3
b. C18H32O16
30. Dairy cattle were unknown in Thai culture until recently, and 97 percent of Thai people are lactose intolerant as adults. Which explanation for such widespread lactose intolerance is most likely correct? a. Allergies are becoming more common in humans as more chemicals are being encountered during longer lifetimes. b. Evolutionarily, producing an enzyme to break down a sugar that will never be encountered is wasteful. c. The ability to digest sugar in milk is determined by environment, and most humans are not exposed to milk as a food source beyond childhood years. d. There is no good explanation for this situation in humans.
b. Evolutionarily, producing an enzyme to break down a sugar that will never be encountered is wasteful.
79. What can you infer about a high molecular weight protein that cannot be transported into the nucleus? a. It is too large. b. It lacks a nuclear localization signal (NLS). c. It contains errors in its amino acid sequence. d. It lacks a signal sequence.
b. It lacks a nuclear localization signal (NLS).
85. How is the structure of kinesin related to its function? a. Kinesin has two intertwined polypeptides that make up the stalk and enable it to contract and shorten. b. Kinesin has a tail region that binds to vesicles and two heads that can attach to microtubules. c. The kinesin tail has an ATP binding site to fuel its activities. d. Kinesin has two heads to attach to the vesicle being moved and a tail region that attaches to microtubules
b. Kinesin has a tail region that binds to vesicles and two heads that can attach to microtubules.
82. Scientists have found that polypeptides that are normally synthesized in the endoplasmic reticulum are about 20 amino acids longer when they are synthesized by ribosomes not attached to the endoplasmic reticulum. What is a possible explanation for the greater length of these polypeptides? a. Ribosomes attached to the endoplasmic reticulum require fewer amino acids to function. b. The 20 amino acids serve as a signal (peptide) sequence that directs the forming polypeptides to the endoplasmic reticulum, where they are cleaved off during processing. c. The 20-amino-acid sequence helps the endoplasmic reticulum package these proteins for shipping to the Golgi. d. The protein has a different function in the cytosol than in the endoplasmic reticulum.
b. The 20 amino acids serve as a signal (peptide) sequence that directs the forming polypeptides to the endoplasmic reticulum, where they are cleaved off during processing.
8. DNAase is an enzyme that catalyzes the hydrolysis of the covalent bonds that join nucleotides together. What would first happen to DNA molecules treated with DNAase? a. The two strands of the double helix would separate. b. The phosphodiester bonds between deoxyribose sugars would be broken. c. The purines would be separated from the deoxyribose sugars. d. The pyrimidines would be separated from the deoxyribose sugars. e. All bases would be separated from the deoxyribose sugars.
b. The phosphodiester bonds between deoxyribose sugars would be broken.
19. Enzymes that break down DNA catalyze the hydrolysis of the covalent bonds that join nucleotides together. What would happen to DNA molecules treated with these enzymes? a. The two strands of the double helix would separate. b. The phosphodiester linkages of the polynucleotide backbone would be broken. c. The purines would be separated from the deoxyribose sugars. d. The pyrimidines would be separated from the deoxyribose sugars. e. All bases would be separated from the deoxyribose sugars.
b. The phosphodiester linkages of the polynucleotide backbone would be broken.
72. Steroid hormones are large communication molecules that are modified cholesterol molecules. How do you think they enter a cell? a. Their size probably allows them to diffuse through the plasma membrane. b. Their lipid nature probably allowsthem to diffuse through the plasma membrane. c. Their protein structure probably allows them to diffuse through the plasma membrane. d. They must require a protein transporter, because the plasma membrane is completely impermeable to molecules.
b. Their lipid nature probably allowsthem to diffuse through the plasma membrane.
29. A glycosidic linkage is analogous to which of the following in proteins? a. an amino group b. a peptide bond c. a disulfide bond d. a β-pleated sheet
b. a peptide bond
18. What is the structural feature that allows DNA to replicate? a. sugar-phosphate backbone b. complementary pairing of the nitrogenous bases c. disulfide bonding (bridging) of the two helixes d. twisting of the molecule to form an α-helix e. three-component structure of the nucleotides
b. complementary pairing of the nitrogenous bases
38. You isolate an organic molecule that contains C, H, O, N, and S. This molecule _____. a. is a disaccharide b. could be a glycoprotein c. is a nucleic acid d. could be cellulose or glycogen
b. could be a glycoprotein
83. Lysosomes that lack mannose-6-phosphate receptors _____. a. receive "modified" enzymes and are thus unable to break down carbohydrates b. do not receive enzyme shipments from the Golgi apparatus c. have unstable membranes d. stick to transport vesicles and impede the transfer of enzymes
b. do not receive enzyme shipments from the Golgi apparatus
7. In the acid-base reaction described in the preceding paragraph about Nakano's research on RNAs, a proton (H+) is being transferred. What is acting as the proton acceptor? a. cytosine b. magnesium hydroxide c. the virus d. cytosine, magnesium hydroxide, or the virus
b. magnesium hydroxide
58. Refer to the figure. At the beginning of the experiment, a. side A is hypertonic to side B. b. side A is hypotonic to side B. c. side A is isotonic to side B. d. side A is hypertonic to side B with respect to glucose. e. side A is hypotonic to side B with respect to NaCl.
b. side A is hypotonic to side B.
77. The liver is involved in detoxification of many poisons and drugs. Which of the following structures is primarily involved in this process and, therefore, abundant in liver cells? a. rough ER b. smooth ER c. Golgi apparatus d. nuclear envelope e. transport vesicles
b. smooth ER
48. What region of a steroid is hydrophilic? a. the methyl (-CH3) groups b. the terminal hydroxyl group c. the ring structures d. the long hydrocarbon chain
b. the terminal hydroxyl group
9. If a DNA sample were composed of 10% thymine, what would be the percentage of guanine? a. 10 b. 20 c. 40 d. 80 e. It is impossible to tell from the information given.
c. 40
51. Which of the following is the best explanation for why cholesterol decreases the permeability of biological membranes? a. Cholesterol binds to the outside surface of a membrane, thus blocking the movement of solutes. b. Because cholesterol is amphipathic, it forms tiny vesicles that trap solutes. c. Because cholesterol is amphipathic, it fits in between the phospholipids and blocks diffusion through the membrane. d. Cholesterol has four rings in its structure that can sequester (trap) solutes.
c. Because cholesterol is amphipathic, it fits in between the phospholipids and blocks diffusion through the membrane.
60. Which line in the graph represents the bag that contained a solution isotonic to the 0.6 M solution at the beginning of the experiment? a. A b. B c. C d. D e. E
c. C
37. The molecular formula for glucose is C6H12O6. What would be the molecular formula for a polymer made by linking ten glucose molecules together by dehydration reactions? a. C60H120O60 b. C6H12O6 c. C60H102O51 d. C60H100O50 e. C60H111O51
c. C60H102O51
41. Which of the following best explains why manufacturers of candy bars and sports drinks advertise "carbs" (carbohydrates) as a "quick energy boost"? a. The energy in them can be stored as fat, which has high energy per unit weight. b. The carbons in carbohydrates are rich in energy because they are highly oxidized. c. Carbohydrates are reduced molecules that have high-energy electrons. d. This is an advertising gimmick that has no scientific evidence to support it.
c. Carbohydrates are reduced molecules that have high-energy electrons.
63. Gramicidin is an antibiotic that increases the permeability of bacterial cell walls to inorganic ions. What is the most likely mode of action of gramicidin? a. It acts by active transport. b. It causes membranes to fuse with one another. c. It forms a channel in the membrane. d. It removes electrical charges from solutes.
c. It forms a channel in the membrane.
13. Nucleic acids have a definite polarity, or directionality. Stated another way, one end of the molecule is different from the other end. How are these ends described? a. One end has a hydroxyl group on the 2-carbon; the other end has a hydrogen atom on the 2-carbon. b. One end contains a nitrogenous base; the other end lacks it. c. One end has an unlinked 3 carbon; the other end has an unlinked 5 carbon. d. One end has one phosphate group; the other end has two phosphate groups.
c. One end has an unlinked 3 carbon; the other end has an unlinked 5 carbon.
21. If 14C-labeled uracil is added to the growth medium of cells, what macromolecules will be labeled? a. phospholipids b. DNA c. RNA d. both DNA and RNA e. proteins
c. RNA
53. You have just discovered an organism that lives in extremely cold environments. Which of the following would you predict to be true about the phospholipids in its membranes, compared to phospholipids in the membranes of organisms that live in warmer environments? a. The membrane phospholipids of cold-adapted organisms will have longer hydrocarbon tails. b. The membrane phospholipids of cold-adapted organisms will have more saturated hydrocarbon tails. c. The membrane phospholipids of cold-adapted organisms will have more unsaturated hydrocarbon tails.
c. The membrane phospholipids of cold-adapted organisms will have more unsaturated hydrocarbon tails.
62. A patient was involved a serious accident and lost a large quantity of blood. In an attempt to replenish body fluids, distilled water—equal to the volume of blood lost—is added to the blood directly via one of his veins. What will be the most probable result of this transfusion? a. It will have no unfavorable effect as long as the water is free of viruses and bacteria. b. The patient's red blood cells will shrivel up because the blood has become hypotonic compared to the cells. c. The patient's red blood cells will swell and possibly burst because the blood has become hypotonic compared to the cells. d. The patient's red blood cells will shrivel up because the blood has become hypertonic compared to the cells. e. The patient's red blood cells will burst because the blood has become hypertonic compared to the cells
c. The patient's red blood cells will swell and possibly burst because the blood has become hypotonic compared to the cells.
28. Which of the following structural features is common to cellulose, chitin, and peptidoglycan? a. They are all composed of glucose in either the α or β form. b. They all contain peptide bonds. c. They can all form bonds between polymer chains that create parallel strands. d. They are all composed of highly branched fibers.
c. They can all form bonds between polymer chains that create parallel strands.
75. The nuclear lamina is an array of filaments on the inner side of the nuclear membrane. If a method were found that could cause the lamina to fall into disarray, what would you most likely expect to be the immediate consequence? a. the loss of all nuclear function b. the inability of the nucleus to divide during cell division c. a change in the shape of the nucleus d. failure of chromosomes to carry genetic information e. inability of the ribosomes to produce proteins
c. a change in the shape of the nucleus
45. Chitin is a major component of the _____. a. skeleton of mammals b. hydrostatic skeletons of earthworms c. exoskeleton of insects d. body hairs of mammals e. skeleton in birds
c. exoskeleton of insects
80. The difference in lipid and protein composition between the membranes of the endomembrane system is largely determined by the _____. a. interconnection of most intracellular membranes to the nuclear envelope b. transportation of membrane lipids among the membranes of the endomembrane system by small membrane vesicles c. function of the Golgi apparatus in sorting and directing membrane components d. modification of the membrane components once they reach their final destination
c. function of the Golgi apparatus in sorting and directing membrane components
47. Diffusion _____. a. is very rapid over long distances b. requires an expenditure of energy by the cell c. is a passive process in which molecules move from a region of higher concentration to a region of lower concentration d. is an active process in which molecules move from a region of lower concentration to one of higher concentration
c. is a passive process in which molecules move from a region of higher concentration to a region of lower concentration
57. Celery stalks that are immersed in fresh water for several hours become stiff. Similar stalks left in a 0.15 M salt solution become limp. From this we can deduce that the fresh water_____. a. and the salt solution are both hypertonic to the cells of the celery stalks b. and the salt solution are both hypotonic to the cells of the celery stalks c. is hypotonic and the salt solution is hypertonic to the cells of the celery stalks d. is hypertonic and the salt solution is hypotonic to the cells of the celery stalks
c. is hypotonic and the salt solution is hypertonic to the cells of the celery stalks
70. Which of the following membrane activities requires energy from ATP? a. facilitated diffusion of chloride ions across the membrane through a chloride channel b. movement of water into a cell c. movement of Na+ ions from a lower concentration in a mammalian cell to a higher concentration in the extracellular fluid d. movement of glucose molecules into a bacterial cell from a medium containing a higher concentration of glucose than inside the cell e. movement of carbon dioxide out of a paramecium
c. movement of Na+ ions from a lower concentration in a mammalian cell to a higher concentration in the extracellular fluid
42. If you were going to develop a new antibiotic against bacteria, you would probably need to become an expert on which of these carbohydrates? a. glycogen b. chitin c. peptidoglycan d. cellulose e. starch
c. peptidoglycan
5. Which of the following chemical bonds do you think Nakano is referring to in his quote? a. peptide b. glycosidic c. phosphodiester d. ionic
c. phosphodiester
76. Tay-Sachs disease is a human genetic abnormality that results in cells accumulating and becoming clogged with very large, complex, undigested lipids. Which cellular organelle must be involved in this condition? a. the endoplasmic reticulum b. the Golgi apparatus c. the lysosome d. mitochondrion e. membrane-bound ribosomes
c. the lysosome
24. What is the difference between an aldose sugar and a ketose sugar? a. the number of carbons b. the position of the hydroxyl groups c. the position of the carbonyl group d. One is a ring form, the other is a linear chain/
c. the position of the carbonyl group
20. Which of the following pairs of base sequences could form a short stretch of a normal double helix of DNA? a. 5'-purine-pyrimidine-purine-pyrimidine-3' with 3'-purine-pyrimidine-purine-pyrimidine-5' b. 5'-AGCT-3' with 5'-TCGA-3' c. 5'-GCGC-3' with 5'-TATA-3' d. 5'-ATGC-3' with 5'-GCAT-3' e. All of these pairs are correct.
d. 5'-ATGC-3' with 5'-GCAT-3'
67. Which component is a peripheral protein? a. A b. B c. C d. D e. E
d. D
46. Refer to the paragraph about Kawakubo's group. Kawakubo's group created a glycoprotein with a terminal NAG (i.e., a protein with NAG attached to its end). Their hypothesis is that the terminal NAG, and not the protein component, is responsible for the damage to the cell wall in H. pylori. What would be the most appropriate control for testing this hypothesis? a. Grow H. pylori in a test tube (in vitro) with no glycoprotein. b. Destroy the H. pylori by exposing them to a hypotonic solution. Then add the glycoprotein and observe. c. Expose other species of bacteria to the glycoprotein. d. Grow H. pylori in a test tube with a glycoprotein that has its terminal NAG removed.
d. Grow H. pylori in a test tube with a glycoprotein that has its terminal NAG removed.
14. You have a polymer of DNA with 10 adenine bases followed by 10 cytosine bases. If that strand bonded to a strand of 20 thymine bases, how would the double helix shape vary from a typical DNA double helix? a. The double helix would be longer than normal. b. The double helix would be shorter than normal. c. One strand of the double helix would be longer than the other strand. d. The width of the double helix would vary along the length of the strand.
d. The width of the double helix would vary along the length of the strand.
59. Refer to the figure. If you examine side A after three days, you should find _____. a. a decrease in the concentration of NaCl and glucose and an increase in the water level b. a decrease in the concentration of NaCl, an increase in water level, and no change in the concentration of glucose c. no net change in the system d. a decrease in the concentration of NaCl and a decrease in the water level e. no change in the concentration of NaCl and glucose and an increase in the water level
d. a decrease in the concentration of NaCl and a decrease in the water level
86. Cilia and flagella bend because of _____. a. conformational changes in ATP that thrust microtubules laterally b. a motor protein called radial spokes c. the quick inward movements of water by osmosis. d. a motor protein called dynein
d. a motor protein called dynein
52. Which of the following crosses lipid bilayers the fastest? a. a sodium ion b. a small, polar molecule like water c. a large, polar molecule like glucose d. a small, nonpolar molecule like oxygen (O2)
d. a small, nonpolar molecule like oxygen (O2)
36. Which of the following polymers contain nitrogen? a. starch b. glycogen c. cellulose d. chitin e. glucose
d. chitin
15. Which of the following best describes DNA's secondary structure? a. beta-pleated sheet b. double parallel helical strands c. turn-loop-turn d. double antiparallel helical strands
d. double antiparallel helical strands
88. Asbestos is a material that was once used extensively in construction. One risk from working in a building that contains asbestos is the development of asbestosis caused by the inhalation of asbestos fibers. Cells will phagocytize asbestos, but are not able to degrade it. As a result, asbestos fibers accumulate in _____. a. mitochondria b. ribosomes c. peroxisomes d. lysosomes
d. lysosomes
78. Suppose a young boy is always tired and fatigued, suffering from a metabolic disease. Which of the following organelles is most likely involved in this disease? a. lysosomes b. Golgi apparatus c. Ribosomes d. mitochondria
d. mitochondria
73. Which of the following processes includes all others? a. osmosis b. diffusion of a solute across a membrane c. facilitated diffusion d. passive transport e. transport of an ion down its electrochemical gradient
d. passive transport
27. Which of the following molecules contains at least one peptide bond? a. glycogen b. cellulose c. chitin d. peptidoglycan
d. peptidoglycan
90. An organism with a cell wall would most likely be unable to take in materials through _____. a. diffusion b. osmosis c. active transport d. phagocytosis e. facilitated diffusion
d. phagocytosis
81. What is the most likely pathway taken by a newly synthesized protein that will be secreted by a cell? a. ER → Golgi → nucleus b. Golgi → ER → lysosome c. nucleus → ER → Golgi d. ER → Golgi → vesicles that fuse with plasma membrane e. ER → lysosomes → vesicles that fuse with plasma membrane
e. ER → lysosomes → vesicles that fuse with plasma membrane
10. The difference between the sugar in DNA and the sugar in RNA is that the sugar in DNA _____. a. is a six-carbon sugar and the sugar in RNA is a five-carbon sugar b. can form a double-stranded molecule c. is an aldehyde sugar and the sugar in RNA is a keto sugar d. is in the α configuration and the sugar in RNA is in the β configuration e. contains one less oxygen atom
e. contains one less oxygen atom
87. Which structure-function pair is mismatched? a. nucleolus — production of ribosomal subunits b. lysosome — intracellular digestion c. ribosome — protein synthesis d. Golgi — protein trafficking e. microtubule — muscle contraction
e. microtubule — muscle contraction
64. When biological membranes are frozen and then fractured, they tend to break along the middle of the bilayer. The best explanation for this is that _____. a. the integral membrane proteins are not strong enough to hold the bilayer together b. water that is present in the middle of the bilayer freezes and is easily fractured c. hydrophilic interactions between the opposite membrane surfaces are destroyed on freezing d. the carbon-carbon bonds of the phospholipid tails are easily broken e. the hydrophobic interactions that hold the membrane together are weakest at this point
e. the hydrophobic interactions that hold the membrane together are weakest at this point