27. Which of the following is an amino acid?
A)
B)
C)
D)
E)
28. Polymers of amino-acid units are called
A)
metabolites.
B)
nucleic acids.
C)
lipids.
D)
carbohydrates.
E)
proteins.
29. Which of the following is the zwitterionic form of glycine (R = H)?
A)
–NHCH2CO2H
B)
NH2CHCO2H+
C)
+NH2CH2CO2–
D)
+NH3CH2CO2–
E)
NH2CH2CO2–
30. When L-lysine (R = −(CH2)4NH2) is reacted with a large excess of strong acid, which of the
following ions is the predominant species in solution?
A)
B)
C)
D)
E)
31. Near a pH of 5.5, L-lysine (R = −(CH2)4NH2) the major species in aqueous solution is the
diprotonated zwitterion. Given the following acid dissociation constants, what is the correct
structure of the zwitterion?
Functional Group
Ka
carboxylic acid
1.7 x10-2
amine
8.5 x10–10
side chain amine
1.51 x10–11
A)
B)
C)
D)
E)
Test Bank General Chemistry, 10th edition 16
32. Which of the following structures is the best representation for the amino acid cysteine
under physiological conditions?
A)
B)
C)
D)
E)
33. What is the functional group corresponding to a peptide bond?
A)
amine
B)
ether
C)
amide
D)
hemiacetal
E)
carboxylic acid
34. Which of the following represents the linkage connecting amino acids in proteins?
A)
B)
C)
D)
E)
35. Which of the following statements concerning protein structure is/are correct?
1.
The primary structure of a protein is defined as its sequence.
2.
Secondary protein structures include the alpha helix and beta sheet.
3.
Disulfide linkages are sometimes formed by the glycine which can
significantly effect the protein shape.
A)
1 only
B)
2 only
C)
3 only
D)
1 and 2
E)
1, 2, and 3
Test Bank General Chemistry, 10th edition 18
36. The sequence of amino acids held together by peptide bonds in a protein is the
A)
tertiary structure.
B)
hydrogen bonding.
C)
primary structure.
D)
quaternary structure.
E)
secondary structure.
37. How many different tripeptides can be made from two molecules of the amino acid valine
(val) and one molecule of the amino acid alanine (ala)?
A)
4
B)
3
C)
1
D)
5 or more
E)
2
38. Which of the following types of structure in proteins always has/have covalent bonds?
1.
primary structure
2.
secondary structure
3.
tertiary structure
A)
1 only
B)
2 only
C)
3 only
D)
1, and 2
E)
1, 2, and 3
39. Which of the following statements is correct?
A)
Fibrous proteins tend to form long, water-soluble fibers, while globular proteins
tend to form compact, water-soluble shapes.
B)
Fibrous proteins tend to form long, water-insoluble fibers, while globular proteins
tend to form compact, water-soluble shapes.
C)
Fibrous proteins tend to form long, water-insoluble fibers, while globular proteins
tend to form compact, water-insoluble shapes.
D)
Both fibrous proteins and globular proteins tend to form water-soluble structures of
about the same shape.
E)
Fibrous proteins tend to form long, water-soluble fibers, while globular proteins
tend to form compact, water-insoluble shapes.
40. The alpha helix and beta sheet are examples of
A)
protein denaturation.
B)
protein primary structure.
C)
complementary bases.
D)
protein tertiary structure.
E)
protein secondary structure.
41. The overall shape of a protein is maintained by
A)
hydrogen bonding.
B)
ionic bonds.
C)
dipole–dipole bonding.
D)
covalent bonds.
E)
all of these
42. A hemiacetal is formed from
A)
an alcohol and a ketone.
B)
a carboxylic acid and a mercaptan.
C)
an alcohol and an ether.
D)
an aldehyde and an alcohol.
E)
an ester and an amine.
43. What are the building blocks of nucleic acids?
A)
proteins
B)
monosaccharides
C)
lipids
D)
nucleotides
E)
amino acids
44. A fragment of a DNA molecule has the base sequence CTGA. What is the complementary
sequence?
A)
ATGC
B)
AGTC
C)
TCAG
D)
GACT
E)
CTGA
45. The nucleic acid sequence that is complementary to the DNA sequence GAC TAC GTT
AGC is
A)
CTG ATG CAA TCG.
B)
GAC TAC GTT AGC.
C)
CGA TTG CAT CAG.
D)
TCA GCA TGG CTA.
E)
none of these
46. What is the charge on each phosphate group in DNA in an aqueous solution near
physiological pH?
A)
0
B)
1
C)
2
D)
−1
E)
−2
47. Which of the following units is not found in a DNA molecule?
A)
a phosphate group
B)
a peptide bond
C)
an organic base
D)
a five-membered ring
E)
a ribose sugar
48. What is the nitrogenous base that is found in RNA but not in DNA?
A)
thymine
B)
guanine
C)
uracil
D)
cytosine
E)
adenine
49. Double stranded DNA may be represented as a double helix with the two strands held
together by
A)
hydrogen bonds.
B)
covalent bonds.
C)
disulfide bonds.
D)
hydrophobic bonds.
E)
ionic bonds.
Test Bank General Chemistry, 10th edition 22
50. Which of the following 2′-deoxynucleotides contains the base thymine?
A)
B)
C)
D)
E)
Test Bank General Chemistry, 10th edition 23
51. What is the cell structure that contains the cell’s DNA?
A)
chromosome
B)
codon
C)
ribosome
D)
gene
E)
nucleus
52. Where in the cell does protein synthesis cell take place?
A)
ribosome
B)
nucleus
C)
gene
D)
chromosome
E)
codon
53. What is the significance of a “stop codon”?
A)
When it appears in messenger RNA, it is a signal to stop protein biosynthesis.
B)
When it appears in transfer RNA, it is a signal to stop transferring amino acids to
the growing protein chain.
C)
When it appears in DNA, it is a signal to stop chromosome biosynthesis.
D)
When it appears in a protein, it is a signal for the protein to unfold.
E)
When it appears in ribosomal RNA, it is a signal to stop catalyzing protein
biosynthesis.
54. Which of the following is(are) not necessary for protein synthesis at the time and place
where synthesis occurs?
A)
ribosomes
B)
DNA
C)
mRNA
D)
amino acids
E)
tRNA
55. Which type of molecule is responsible for carrying an amino acid to a ribosome?
A)
protein
B)
DNA
C)
ribosomal RNA
D)
messenger RNA
E)
transfer RNA
56. Which type of molecule attaches itself to a ribosome, where it serves as a pattern for protein
biosynthesis?
A)
transfer RNA
B)
protein
C)
DNA
D)
ribosomal RNA
E)
messenger RNA
57. How many RNA nucleotides are in a codon?
A)
1
B)
5
C)
2
D)
4
E)
3