Chapter 20 Nucleic Acids
Multiple Choice
1. Which structures are named correctly? (Sec. 20.2)
O
O
O
a)
b)
c)
d)
CH3
HN
HN
O
N
O
NH2
N
N
N
N
N
N
HN
NH2
N
H
H
H
H
guanine
I
thymine
II
N
adenine
III
uracil
IV
I, II
II, III
III, IV
I, III
2. Which structure is a nucleoside? (Sec. 20.2)
O
NH2
N
N
b)
a)
N
HOH2C O
N
O
N
H
O
O
O
CH3
HN
HOH2C O
HOH2C
N
d)
O
O
O
OH
OH
O
c)
CH3
HN
OH
P O
O
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OH
P O
O
Chapter 20 Nucleic Acids
3. Which structures are named correctly? (Sec. 20.2)
O
NH2
CH3
HN
HOH2C O
N
HOH2C O
O
O
O
CH3
N
N
O
OH
O
P O
O
O
OH
P O
O
O
P O
O
thymidine 5'-monophosphate
I
cytidine 3'-diphosphate
II
O
NH2
N
HN
O
O
P OH2C H2N
O
O
OH
N
N
H
O
O
O
P O
P OH2C
O
O
OH
a)
b)
c)
d)
N
O
OH
adenosine 5'-monophosphate
III
N
N
N
H
OH
adenosine 5'-diphosphate
IV
I, II
II, III
I, IV
II, IV
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Chapter 20 Nucleic Acids
4. Which nucleotides are named correctly? (Sec. 20.2)
O
HN
O
O
N
O
O
OH
P OH2C H2N
O
O
OH
OH
O
5'-TMP
I
CH3
HN
HOH2C O
O
O
O
OH
N
H
OH
3'-GMP
II
NH2
O
O
P O
P OH2C
O
O
N
N
N
O
OH
OH
P O
5'-GDP
IV
O
3'-TDP
III
I, III
II, III
III, IV
II, IV
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N
H
P O
O
O
N
N
O
a)
b)
c)
d)
N
HN
O
P OH2C O
O
O
CH3
Chapter 20 Nucleic Acids
5. What is the correct name for this structure? (Sec. 20.2)
O
CH3
HN
HOH2C O
N
O
O
O
P O
O
a)
b)
c)
d)
5’-dAMP
5’-TMP
3’-AMP
3’-dTMP
6. How do DNA and RNA differ? (Sec. 20.3, 20.4)
I) the position of attachment of phosphate groups
II) the position of attachment of base groups
III) the sugar structure at C-2’
IV) structure of bases
a)
b)
c)
d)
I, II
II, III
III, IV
II, IV
7. Which are the correct pairings of bases in the structure of DNA? (Sec. 20.3)
I) A-C
II) G-T
III) A-G
IV) G-C
V) A-T
VI) C-T
a)
b)
c)
d)
I, II
III, V
III, IV
IV, V
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Chapter 20 Nucleic Acids
8. In both RNA and DNA structures, the phosphate groups are attached to the sugar structure at which positions?
(Sec. 20.3, 20.4)
a)
b)
c)
d)
5’, 5’
3’, 3’
3’, 5’
5’, 3’
9. What is the charge on adenosine phosphate at blood serum pH of 7.4? (Sec. 20.3)
a)
b)
c)
d)
0
–1
–2
–3
10. Which is the complementary tetranucleotide for 5’-AGCT-3’? (Sec. 20.3)
a)
b)
c)
d)
5’-TCGA-3’
5’-CTAG-3’
5’-AGCT-3’
5’-GATC-3’
11. How many nucleotides direct a specific amino acid into a polypeptide sequence? (Sec. 20.5)
a)
b)
c)
d)
1
2
3
4
12. Which is the DNA complement for 5’-ACCGTTAAT-3’? (Sec. 20.3)
a)
b)
c)
d)
5’-ATTAACGGT-3’
5’-GTTACCGGC-3’
5’-TGGCAATTA-3’
5’-CAATGGCCG-3’
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Chapter 20 Nucleic Acids
13. Hydrogen bonding is strongest between which two bases? (Sec. 20.3)
NH2
O
N
O
a)
b)
c)
d)
CH3
HN
N
O
NH2
N
N
N
H
H
I
II
O
N
N
N
HN
NH2
N
H
III
N
H
IV
I, II
I, IV
II, III
II, IV
14. Where does protein synthesis occur? (Sec. 20.4)
a)
b)
c)
d)
chromatin
ribosome
codon
histones
15. Which is the complementary sequence in RNA for the DNA sequence 5’-AATCAGTT-3’? (Sec. 20.4)
a)
b)
c)
d)
5’-AAUCAGUU-3’
5’-AACUGAUU-3’
5’-UUAGUCAA-3’
5’-CCAUCGAA-3’
16. A complete turn of the DNA helix occurs at which distance? (Sec. 20.3)
a)
b)
c)
d)
34 Å
10 Å
20 Å
4Å
17. Which statement about the base mole-percent composition of DNA is true? (Sec. 20.3)
a)
b)
c)
d)
A=G=C=T
(A+G)=(C+T)
(A+T)=(G+C)
There is no relationship
18. The backbone of DNA is best described as: (Sec. 20.3)
a)
b)
c)
d)
pairs of complementary bases
poly(1,3-diol-phosphate esters)
pyrophosphates
sugar glycosides
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Chapter 20 Nucleic Acids
19. Which statements about differences between DNA and RNA are true? (Sec. 20.3, 20.4)
I) The sugar unit is -D-ribose in RNA and -2-deoxyribose in DNA.
II) The pyrimidine bases are uracil and thymine in RNA and cytosine and thymine in DNA.
III) RNA is single stranded, DNA double stranded.
IV) The phosphodiester groups join the 3’ to 5’ ends of sugars in RNA, and join the 5’ to 3’ ends
in DNA.
a)
b)
c)
d)
I, II
I, III
II, III
III, IV
20. Which are types of RNA? (Sec. 20.4)
I) ribosomal
II) histonal
III) helix
IV) transfer
a)
b)
c)
d)
I, II
I, III
II, IV
I, IV
21. Which is the order of increasing percentage in cells of messenger RNA, transfer RNA, ribosomal RNA (least
first)? (Sec. 20.4)
a)
b)
c)
d)
mRNA, tRNA, rRNA
tRNA, rRNA, mRNA
rRNA, tRNA, mRNA
mRNA, rRNA, tRNA
22. Which statements about mRNA codons are correct? (Sec. 20.4)
I) Each amino acid is coded by only one codon.
II) Codons code for several amino acids.
III) UAA, UAG, UGA are stop codons.
IV) Several amino acids are coded by more than one codon.
a)
b)
c)
d)
I, II
III, IV
I, III
II, IV
23. Which is the key to the chain termination method of DNA sequencing? (Sec. 20.6)
a)
b)
c)
d)
polyacrylamide gels
restriction endonucleases
primer
2’,3’-dideoxynucleoside triphosphate
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Chapter 20 Nucleic Acids
24. Which is the key to in vitro DNA replication? (Sec. 20.6)
a)
b)
c)
d)
polyacrylamide gels
restriction endonucleases
primer
2’,3’-dideoxynucleoside triphosphate
25. Which statements about restriction endonucleases are true? (Sec. 20.6)
I) Each cleave DNA at the same site, but leave different fragment lengths.
II) Each recognizes 4 to 8 nucleotides, and cleaves at all sites containing the sequence.
III) Approximately 1000 restriction endonucleases have been isolated and characterized.
IV) Each cleaves the DNA strand by reducing the base off at the sugar 1’ position.
a)
b)
c)
d)
I, IV
II, IV
II, III
III, IV
Fill in the Blank
1. The name of the following base is ____________________________. (Sec. 20.2)
O
HN
O
N
H
2. The name of the following nucleoside is _____________________________________. (Sec. 20.2)
O
N
HN
H2N
N
N
CH2OH
O
OH
OH
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Chapter 20 Nucleic Acids
3. The name of the following nucleotide is _____________________________________. (Sec. 20.2)
NH2
N
O
O
O
P O CH2
O
N
O
OH
OH
4. The complementary DNA single strand of 5’-AGTGTTCCAGT-3’ is
5’-____________________________-3’. (Sec. 20.3)
5. The complementary RNA strand to the DNA single strand 5’-GGACTTGACTA-3’ is
5’-____________________________-3’. (Sec. 20.4)
6. The first four amino acids of the protein coded for by AUUAUCCAUAAUGGUGGAAAACGA are
__________________________________________________________. (Sec. 20.5)
7. The first four amino acids of the protein coded for by GCUGCCGAUGACGGACGGUGGUGU are
__________________________________________________________. (Sec. 20.5)
8. An mRNA strand that codes for the pentapeptide Ile-Thr-Pro-Lys-Arg could have __________ codons in the first
position. (Sec. 20.5)
9. An mRNA strand that codes for the pentapeptide Met-Ser-Tyr-Met-Cys could have __________ codons in the
first position. (Sec. 20.5)
10. The original DNA strand that results in the following fragments after the Dideoxy method is
5’-_____________________________-3’. (Sec. 20.6)
Primer = AGCT
Fragments AAGCT, GAAGCT, AGAAGCT, AAGAAGCT, CAAGAAGCT, TCAAGAAGCT
True-False
1. The following nucleoside is named Cytidine. (Sec. 20.2)
NH2
N
O
O
O
P O CH2
O
OH
N
O
OH
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Chapter 20 Nucleic Acids
2. The following nucleotide is named 5’-Guanisine diphosphate. (Sec. 20.2)
O
N
HN
P O
H2N
H2
P O C
O
O
O
O
O
N
N
O
OH
OH
3. The mole % of purine bases must be equal in human DNA. (Sec. 20.3)
4. The tertiary structure of DNA involves supercoiling. (Sec. 20.3)
5. t-RNA is the lowest molecular weight and most abundant of the RNAs. (Sec. 20.4)
6. mRNA is the shortest lived of the RNAs and the least abundant. (Sec. 20.4)
7. The complementary strand of mRNA to the DNA sequence TAGAAGTAG is ATCTTCATC. (Sec. 20.4)
8. tRNA with the codon UGA codes for Cys. (Sec. 20.5)
9. If the smallest fragment produced during the Dideoxy method and separated by PAGE includes the primer and
the base T, the original DNA template begins with T after the primer sequence. (Sec. 20.6)
10. The Chain Termination method uses dideoxy nucleosides to stop DNA synthesis. (Sec. 20.6)
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Chapter 20 Nucleic Acids
Answers
Multiple Choice
1. b
2. c
3. d
4. a
5. d
6. c
7. d
8. c
9. c
10. c
11. c
12. a
13. b
14. b
15. b
16. a
17. b
18. b
19. b
20. d
21. a
22. b
23. d
24. c
25. c
Fill in the Blank
1. Thymine
2. Guanisine
3. 5’-cytidine monophosphate
4. 5’-ACTGGAACACT-3’
5. 5’-UAGUCAAGUCC-3’
6. Ile-Ile-His-Asn
7. Ala-Ala-Asp-Asp
8. 3
9. 1
10. 5’-AGTTCT-3’
True-False
1. F
2. T
3. F
4. T
5. F
6. T
7. F
8. F
9. F
10. T
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