Deck 26: Nucleosides, Nucleotides, and Nucleic Acids

Question 1

Approximately $30 \%$ of the bases found in human DNA are adenine. Based on this, what is the approximate percentage of guanine found in human DNA?

A) $20 \%$
B) $30 \%$
C) $60 \%$
D) $70 \%$

Answer 1

$20 \%$

Question 2

The base pairs present in DNA are
A. A----G and C----T.
B. A----C and G----T.
C. A----T and G----C.
D. A----A and T----T.

A) A
B) B
C) C
D) D

Answer 2

C

Question 3

Which one of the following is in DNA but not in RNA?

A) adenine
B) uracil
C) guanine
D) thymine

Answer 3

thymine

Question 4

How many bases constitute a codon in messenger RNA?

A) one
B) two
C) three
D) four

Question 5

The carbohydrate in RNA is in the

A) open-chain form.
B) furanose form.
C) pyranose form.
D) ketose form.

Question 6

How is the following structure classified?

A) DNA base
B) nucleoside
C) nucleotide
D) nucleic acid

Question 7

Which of the following DNA base sequences is the complementary strand to the DNA sequence shown below? (Recall: DNA strands run antiparallel.)
(5') GGATTCGA (3')

A) (5') CCTAAGCT (3')
B) (5') TGCAATGG (3')
C) (5') TCGAATCC (3')
D) (5') CCTAAGGT (3')

Question 8

A codon in a segment of mRNA is shown below. Which of the following is the corresponding anticodon?
(5') G-A-U (3')

A) (5') A-U-C (3')
B) (5') C-U-A (3')
C) (5') C-G-A (3')
D) (5') G-C-A (3')

Question 9

The codon sequences on a segment of mRNA are shown below. Which of the following amino acid sequences is coded by this mRNA segment? (Recall: the mRNA chain runs 5' to 3'. Refer to table 28.3 in the textbook.)
-UAC-GCA-CCC-ACG-AGC-CAG-

A) tyr-arg-ala-pro-thr-pro
B) gln-ser-pro-ala-arg-tyr
C) ser-gly-ala-ile-thr-lys
D) tyr-ala-pro-thr-ser-gln

Question 10

The structures of cytosine and guanine are shown below. In DNA the $-\mathrm{NH}_{2}$ group on guanine hydrogen bonds with the

A) - $\mathrm{NH}_{2}$ group on cytosine.
B) doubly bonded ring nitrogen on cytosine.
C) -NH- ring nitrogen on cytosine.
D) carbonyl oxygen on cytosine.

Question 11

The repeating unit found in the backbone structure of DNA is

A) [base-sugar].
B) [base-phosphate].
C) [sugar-phosphate].
D) [base-phosphate-sugar].

Question 12

Which of the following is the "enol" form of guanine?

A)

B)

C)

D)

Question 13

Peptide biosynthesis is mechanistically similar to the

A) Claisen condensation.
B) aldol condensation.
C) Fischer esterification reaction.
D) ammonolysis of an ester.

Question 14

The term retrovirus refers to what?

A) a virus that reverse copies its host's DNA.
B) a virus whose DNA does not reside in an anti-parallel arrangement.
C) a virus that uses RNA as its genetic material.
D) a virus that contains cyclic DNA.

Question 15

How many "start" and "stop" codons, respectively, are there in the genetic code?

A) one of each
B) one "start", three "stop"
C) two "start" and two "stop"
D) two "start" and one "stop"