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3. Which of the following is characteristic of proteins?
a. They are insoluble in water.
b. They are the structural units of glycogen.
c. They possess glycosidic linkages between amino acids.
d. Some function as enzymes.
e. a, b, and c
Answer: d
4. Molecules with molecular weights greater than 1,000 daltons are usually called
a. proteins.
b. polymers.
c. nucleic acids.
d. macromolecules.
e. monomers.
Answer: d
5. Polymerization reactions in which proteins are synthesized from amino acids
a. require the formation of phosphodiester bonds between the amino acids.
b. occur in the nucleus of the cell.
c. are hydrolysis reactions.
d. depend upon van der Waals forces to hold the amino acids together.
e. result in the formation of water.
Answer: e
7. Which of the following is not a macromolecule?
a. RNA
b. DNA
c. An enzyme
d. A protein
e. Salt
Answer: e
8. The bonds that form between the monomers in macromolecules are _______ bonds.
a. hydrogen
b. peptide
c. disulfide
d. covalent
e. ionic
Answer: d
10. 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?
a. Carbohydrates
b. Lipids
c. Proteins
d. Enzymes
e. Nucleic acids
Answer: b
12. 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?
a. The oil now has a lower melting point.
b. The oil is now a solid at room temperature.
c. There are more “kinks” in the fatty acid chains.
d. The oil is now a derivative carbohydrate.
e. The fatty acid is now a triglyceride.
Answer: b
13. The portion of a phospholipid that contains the phosphorous group has one or more
electric charges. That makes this region of the molecule
a. hydrophobic.
b. hydrophilic.
c. nonpolar.
d. unsaturated.
e. saturated.
Answer: b
16. 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
a. hydrophobic.
b. hydrophilic.
c. charged.
d. polar.
e. filled with water.
Answer: a
17. The monomers that make up polymeric carbohydrates like starch are called
a. nucleotides.
b. trisaccharides.
c. monosaccharides.
d. nucleosides.
e. fatty acids.
Answer: c
19. Glucose and fructose both have the formula C6H12O6, but the atoms in these two
compounds are arranged differently. Glucose and fructose are known as
a. isomers.
b. polysaccharides.
c. oligosaccharides.
d. pentoses.
e. steroids.
Answer: a
20. A nucleotide contains a pentose, a phosphate, and a(n)
a. lipid.
b. acid.
c. nitrogen-containing base.
d. amino acid.
e. glycerol.
Answer: c
21. A simple sugar such as ribose with the formula C5H10O5 can be classified as a
a. hexose.
b. polysaccharide.
c. disaccharide.
d. pentose.
e. lipid.
Answer: d
23. Two important polysaccharides made up of glucose monomers are
a. guanine and cytosine.
b. RNA and DNA.
c. sucrose and lactose.
d. cellulose and starch.
e. testosterone and cortisone.
Answer: d
25. Cellulose is the most abundant organic compound on Earth. Its main function is
a. to store genetic information.
b. as a storage compound for energy in plant cells.
c. as a storage compound for energy in animal cells.
d. as a component of biological membranes.
e. to provide mechanical strength to plant cell walls.
Answer: e
27. Which of the following monomer/polymer pairs is not correct?
a. Monosaccharide/polysaccharide
b. Amino acid/protein
c. Triglyceride/lipid
d. Nucleotide/DNA
e. Nucleotide/RNA
Answer: c
28. Amino acids can be classified by the
a. number of monosaccharides they contain.
b. number of carbon–carbon double bonds in their fatty acids.
c. number of peptide bonds they can form.
d. number of disulfide bridges they can form.
e. characteristics of their side chains.
Answer: e
29. During the formation of a peptide linkage, which of the following occurs?
a. A molecule of water is formed.
b. A disulfide bridge is formed.
c. A hydrophobic bond is formed.
d. A hydrophilic bond is formed.
e. An ionic bond is formed.
Answer: a
32. The shape of a folded protein is often determined by
a. its fatty acid composition.
b. the sequence of its amino acids.
c. whether the peptide bonds have a or b linkages.
d. the number of peptide bonds.
e. the base-pairing rules.
Answer: b
34. What is the nucleotide sequence of the complementary strand of this DNA molecule:
A A T G C G A?
a. T T A C G C T
b. A A T G C G A
c. G G C A T A G
d. C C G T T A T
e. A G C G T A A
Answer: a
35. Which of the following is not a difference between DNA and RNA?
a. DNA has thymine, whereas RNA has uracil.
b. DNA usually has two polynucleotide strands, whereas RNA usually has one strand.
c. DNA has deoxyribose sugar, whereas RNA has ribose sugar.
d. DNA is a polymer, whereas RNA is a monomer.
e. In DNA, A pairs with T, whereas in RNA, A pairs with U.
Answer: d
38. According to the base-pairing rules for nucleic acids, purines always pair with
a. deoxyribose sugars.
b. uracil.
c. pyrimidines.
d. adenine.
e. guanine.
Answer: c
39. What type of amino acid side chains would you expect to find on the outer surface of
a protein that exists in an aquatic environment.
a. Cysteine
b. Hydrophobic
c. Hydrophilic
d. Charged
e. Polar, but not charged
Answer: b
43. Sucrose is a
a. hexose.
b. lipid.
c. disaccharide.
d. glucose.
e. simple sugar.
Answer: c
44. DNA and RNA contain
a. pentoses.
b. hexoses.
c. fructoses.
d. maltoses.
e. amyloses.
Answer: a
45. The 20 different common amino acids have different
a. amino groups.
b. R groups.
c. acid groups.
d. peptide linkages.
e. primary structures.
Answer: b
46. The primary structure of a protein is determined by its
a. disulfide bridges.
b. a helix structure.
c. sequence of amino acids.
d. branching.
e. three-dimensional structure.
Answer: c
47. When a protein loses its three-dimensional structure and becomes nonfunctional, it is
a. permanent.
b. reversible.
c. denatured.
d. hydrolyzed.
e. environmentalized.
Answer: c
48. A β pleated sheet organization in a polypeptide chain is an example of _______
structure.
a. primary
b. secondary
c. tertiary
d. quaternary
e. coiled
Answer: b
49. A protein can best be defined as a polymer
a. of amino acids.
b. containing one or more polypeptide chains.
c. containing 20 amino acids.
d. containing 20 peptide linkages.
e. containing double helices.
Answer: a
50. The four nitrogenous bases of RNA are abbreviated as
a. A, G, C, and T.
b. A, G, T, and N.
c. G, C, U, and N.
d. A, G, U, and T.
e. A, G, C, and U.
Answer: e
54. A molecule that has an important role in limiting what gets into and out of cells is
a. glucose.
b. maltose.
c. phospholipid.
d. fat.
e. phosphohexose.
Answer: c
57. A peptide linkage (peptide bond) holds together two _______ molecules.
a. protein
b. amino acid
c. sugar
d. fatty acid
e. phospholipid
Answer: b
62. Enzymes are
a. DNA.
b. lipids.
c. carbohydrates.
d. proteins.
e. amino acids.
Answer: d
63. The type of bond that holds two amino acids together in a polypeptide chain is a(n)
a. ionic bond.
b. disulfide bridge.
c. hydrogen bond.
d. peptide linkage.
e. dehydration bond.
Answer: d
67. In DNA, A hydrogen bonds with T and G with C; this is an example of
a. complementary base pairing.
b. a dehydration reaction.
c. a reduction reaction.
d. a hydrophobic reaction.
e. a purine–purine reaction.
Answer: a
68. A fat contains fatty acids and
a. glycerol.
b. a base.
c. an amino acid.
d. a phosphate.
e. None of the above
Answer: a
81. The double helix structure of DNA is due to
a. complementary base pairings.
b. purines bonding with pyrimidines.
c. the phosphodiester bonds between deoxyribose and phosphate.
d. hydrogen bonding of the two complementary polynucleotide strands.
e. ionic bonding of base pairs.
Answer d
82. Spontaneous generation was disproved by
a. Miller.
b. Urey.
c. Pasteur.
d. Allan Hills.
e. van der Waal.
Answer c