1) Which of these classes of biological molecules does NOT include polymers?
A) lipids
B) carbohydrates
C) proteins
D) nucleic acids
Answer: A
2) Which of the following is NOT a polymer? A) glucose
B)
starch
C) cellulose
D) DNA
Answer: A
3) How many molecules of water are used to completely hydrolyze a
polymer that is 11 monomers long?
A) 12
B) 11
C) 10
D) 9
Answer: C
4) Which of the following best summarizes the relationship between
dehydration reactions and hydrolysis?
A) Dehydration reactions
assemble polymers; hydrolysis reactions break polymers apart.
B)
Dehydration reactions eliminate water from membranes; hydrolysis
reactions add water to membranes.
C) Dehydration reactions and hydrolysis reactions assemble polymers from monomers.
D) Hydrolysis reactions create polymers and dehydration reactions create monomers.
Answer: A
5) 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
Answer: B
6) 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
Answer: C
7) What is the major structural difference between starch and glycogen?
A) the types of monosaccharide subunits in the molecules
B)
the type of glycosidic linkages in the molecule
C) whether
glucose is in the α or β form
D) the amount of branching that occurs in the molecule
Answer: D
8) Which polysaccharide is an important component in the structure of many animals and fungi?
A) chitin
B) cellulose
C) amylopectin
D) amylose
Answer: A
9) What does the term insoluble fiber refer to on food packages?
A) cellulose
B) polypeptides
C) starch
D) amylopectin
Answer: A
10) A molecule with the chemical formula C6H12O6 is probably a _____.
A) fatty acid
B) polysaccharide
C) nucleic acid
D) monosaccharide
Answer: D
11) Lactose, a sugar in milk, is composed of one glucose molecule
joined by a glycosidic linkage to one galactose molecule. How is
lactose classified?
A) as a hexose
B) as a monosaccharide
C) as a disaccharide
D) as a polysaccharide
Answer: C
12) Starch and cellulose _____.
A) are polymers of
glucose
B) are cis-trans isomers of each other
C) are used
for energy storage in plants
D) are structural components of the
plant cell wall
Answer: A
13) 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) starch
monomers are joined by covalent bonds and cellulose monomers are
joined by ionic bonds
C) the monomer of starch is glucose, while
the monomer of cellulose is galactose
D) the monomer of starch
is fructose, while the monomer of cellulose is glucose
Answer: A
15) 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
Answer: B
16) 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
Answer: A
17) How do phospholipids interact with water molecules?
A) The
polar heads avoid water; the nonpolar tails attract water (because
water is polar and opposites attract).
B) Phospholipids do not
interact with water because water is polar and lipids are nonpolar.
C) The polar heads interact with water; the nonpolar tails do
not.
D) Phospholipids dissolve in water.
Answer: C
18) Phospholipids and triglycerides both _____.
A) contain serine or some other organic compound
B) have three fatty acids
C) have a glycerol backbone
D) have a phosphate
Answer: C
19) Which of the following is the best explanation for why vegetable
oil is a liquid at room temperature while animal fats are solid?
A) Vegetable oil has more double bonds than animal fats.
B)
Vegetable oil has fewer double bonds than animal fats.
C) Animal fats have no amphipathic character.
D) Vegetable
oil has longer fatty-acid tails than animal fats have.
Answer: A
20) Which of the following statements is FALSE? Saturated fats _____.
A) are more common in animals than in plants
B) have many
double bonds in the carbon chains of their fatty acids
C)
usually solidify at room temperature
D) contain more hydrogen than unsaturated fats that consist of the same number of carbon atoms
Answer: B
21) Lipids _____.
A) are insoluble in water
B) are made
from glycerol, fatty acids, and nitrogen
C) contain less energy than proteins and carbohydrates
D) are made by dehydration reactions
Answer: A
22) The label on a container of margarine lists "hydrogenated
vegetable oil" as the major ingredient. Hydrogenated vegetable
oil _____.
A) is solid at room temperature
B) has more
"kinks" in the fatty acid chains
C) has fewer trans fatty acids
D) is less likely to clog arteries
Answer: A
23) Saturated fatty acids _____.
A) have double bonds between
carbon atoms of the fatty acids
B) are the principal molecules in lard and butter
C) are
usually liquid at room temperature
D) are usually produced by plants
Answer: B
24) Steroids are considered to be lipids because they _____.
A) are essential components of cell membranes
B) are not
soluble in water
C) are made of fatty acids
D) contribute to atherosclerosis
Answer: B
27) Which one of the following is NOT a component of each monomer used to make proteins?
A) a phosphorus atom, P
B) an amino functional group, NH2
C) a side chain, R
D) a carboxyl group, COOH
Answer: A
28) What component of amino acid structure varies among different amino acids?
A) the long carbon-hydrogen tails of the molecule
B) the
presence of a central C atom
C) the components of the R-group
D) the glycerol molecule that forms the backbone of the amino acid
Answer: C
29) You disrupt all hydrogen bonds in a protein. What level of structure will be preserved?
A) primary structure
B) secondary structure
C) tertiary structure
D) quaternary structure
Answer: A
30) Which of the following is the strongest evidence that protein
structure and function are correlated?
A) Proteins function best
at certain temperatures.
B) Proteins have four distinct levels
of structure and many functions.
C) Enzymes tend to be globular in shape.
D) Denatured
(unfolded) proteins do not function normally.
Answer: D
31) You have just sequenced a new protein found in mice and observe
that sulfur-containing cysteine residues occur at regular intervals.
What is the significance of this finding?
A) Cysteine residues
are required for the formation of α-helices and β-pleated
sheets.
B) It will be important to include cysteine in the diet
of the mice.
C) Cysteine residues are involved in disulfide bridges that help form tertiary structure.
D) Cysteine causes bends, or angles, to occur in the tertiary structure of proteins.
Answer: C
Rhodopsins are light-sensitive molecules composed of a protein (opsin) and retinal (derivative of vitamin A). Opsin is a membrane protein with several α-helical segments that loop back and forth through the plasma membrane. There are two classes of rhodopsins. According to Oded Beje, one class has relatively slow dynamics (a photocycle of approximately 0.5 second) and is well suited for light detection. The second class has faster dynamics (a photocycle of approximately 0.02 seconds) and is well suited for chemiosmosis: pumping of protons or chloride ions across cell membranes. Oded Beje was the first, in September 2000, to report on a rhodopsin (proteorhodopsin) found in the domain Bacteria. [SOURCE: O. Beje et al., Science 289 (2000): 1902.]
32) Proteorhodopsin consists of a single polypeptide chain. What is
the highest level of structure found in this protein?
A)
primary
B) secondary
C) tertiary
D) quaternary
Answer: C
Use the following information when answering the corresponding question(s).
Rhodopsins are light-sensitive molecules composed of a protein (opsin) and retinal (derivative of vitamin A). Opsin is a membrane protein with several α-helical segments that loop back and forth through the plasma membrane. There are two classes of rhodopsins. According to Oded Beje, one class has relatively slow dynamics (a photocycle of approximately 0.5 second) and is well suited for light detection. The second class has faster dynamics (a photocycle of approximately 0.02 seconds) and is well suited for chemiosmosis: pumping of protons or chloride ions across cell membranes. Oded Beje was the first, in September 2000, to report on a rhodopsin (proteorhodopsin) found in the domain Bacteria. [SOURCE: O. Beje et al., Science 289 (2000): 1902.]
33) All of the following contain amino acids EXCEPT _____.
A) hemoglobin
B) cholesterol
C) enzymes
D) insulin
Answer: B
Use the following information when answering the corresponding question(s).
Rhodopsins are light-sensitive molecules composed of a protein (opsin) and retinal (derivative of vitamin A). Opsin is a membrane protein with several α-helical segments that loop back and forth through the plasma membrane. There are two classes of rhodopsins. According to Oded Beje, one class has relatively slow dynamics (a photocycle of approximately 0.5 second) and is well suited for light detection. The second class has faster dynamics (a photocycle of approximately 0.02 seconds) and is well suited for chemiosmosis: pumping of protons or chloride ions across cell membranes. Oded Beje was the first, in September 2000, to report on a rhodopsin (proteorhodopsin) found in the domain Bacteria. [SOURCE: O. Beje et al., Science 289 (2000): 1902.]
34) Which level of protein structure do the α-helix and the
β-pleated sheet represent? A) primary
B) secondary
C) tertiary
D) quaternary
Answer: B
35) The tertiary structure of a protein is the _____.
A) order
in which amino acids are joined in a polypeptide chain
B) unique
three-dimensional shape of the fully folded polypeptide
C)
organization of a polypeptide chain into an α-helix or β-pleated
sheet
D) overall protein structure resulting from the
aggregation of two or more polypeptide subunits
Answer: B
36) The R-group, or side chain, of the amino acid serine is -CH2-OH. The R-group, or side chain, of the amino acid leucine is -CH2-CH-(CH3)2. Where would you expect to find these amino acids in a globular protein in aqueous solution?
A) Serine would be in the interior, and leucine would be on the exterior of the globular protein.
B) Leucine would be in the interior, and serine would be on the exterior of the globular protein.
C) Serine and leucine would both be in the interior of the globular
protein.
D) Serine and leucine would both be on the exterior of
the globular protein.
Answer: B
37) Misfolding of polypeptides is a serious problem in cells. Which
of the following diseases are associated with an accumulation of
misfolded polypeptides?
A) Alzheimer's only
B) Parkinson's only
C) diabetes mellitus only
D) Alzheimer's and Parkinson's only
Answer: D
38) Changing a single amino acid in a protein consisting of 325 amino acids would _____.
A) alter the primary structure of the protein but not its tertiary
structure or function
B) cause the tertiary structure of the
protein to unfold
C) always alter the biological activity or
function of the protein
D) always alter the primary structure of the protein, sometimes alter the tertiary structure of the protein, and sometimes affect its biological activity
Answer: D
39) Normal hemoglobin is a tetramer, consisting of two molecules of β hemoglobin and two molecules of α hemoglobin. In sickle-cell disease, as a result of a single amino acid change, the mutant hemoglobin tetramers associate with each other and assemble into large fibers. Based on this information alone, we can conclude that sickle-cell hemoglobin exhibits _____.
A) only altered primary structure
B) only altered tertiary
structure
C) only altered quaternary structure
D) altered
primary structure and altered quaternary structure; the secondary and
tertiary structures may or may not be altered
Answer: D
40) What is the term used for a protein molecule that assists in the
proper folding of other proteins?
A) tertiary protein
B) chaperonin
C) renaturing protein
D) denaturing protein
Answer: B
42) Nucleic acids are polymers made up of which of the following monomers?
A) nucleotides
B) sugars
C) amino acids
D) nitrogenous bases
Answer: A
43) Which of the following includes all of the pyrimidines found in RNA and DNA?
A) cytosine and uracil
B) cytosine and thymine
C)
cytosine, uracil, and thymine
D) cytosine, uracil, and guanine
Answer: C
44) 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
Answer: A
45) Which of the following statements about the 5' end of a
polynucleotide strand of RNA is correct?
A) The end has a
hydroxyl group attached to the number 5 carbon of ribose.
B) The
end has a phosphate group attached to the number 5 carbon of ribose.
C) The end has phosphate attached to the number 5 carbon of the nitrogenous base. D) The end has a carboxyl group attached to the number 5 carbon of ribose.
Answer: B
46) One of the primary functions of RNA molecules is to _____.
A) transmit genetic information to offspring
B) function in
the synthesis of proteins
C) make a copy of itself, thus
ensuring genetic continuity
D) act as a pattern or blueprint to form DNA
Answer: B
47) If 14C-labeled uracil is added to the growth medium of cells,
what macromolecules will be labeled?
A) DNA
B) RNA
C) both DNA and RNA
D) proteins
Answer: B
48) Which of the following descriptions best fits the class of molecules known as nucleotides?
A) a nitrogenous base and a phosphate group
B) a nitrogenous
base and a sugar
C) a nitrogenous base, a phosphate group, and a sugar
D) a sugar and a purine or pyrimidine
Answer: C
49) If a DNA sample were composed of 10% thymine, what would be the
percentage of guanine?
A) 10
B) 40
C) 80
D) It is impossible to tell from the information given.
Answer: B
50) Which of the following statements best summarizes the differences between DNA and RNA?
A) DNA encodes hereditary information, whereas RNA does not.
B) The bases in DNA contain sugars, whereas the bases in RNA do not
contain sugar.
C) DNA nucleotides contain a different sugar than
RNA nucleotides.
D) DNA contains the base uracil, whereas RNA contains the base thymine.
Answer: C
51) 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) 3'UAACGU5'
D) 5'UGCAAU3'
Answer: B
60) A new organism is discovered in the forests of Costa Rica. Scientists there determine that the polypeptide sequence of hemoglobin from the new organism has 72 amino acid differences from humans, 65 differences from a gibbon, 49 differences from a rat, and 5 differences from a frog. These data suggest that the new organism is more closely related to _____.
A) humans than to frogs
B) frogs than to humans
C) rats than to frogs
D) gibbons than to rats
Answer: B