1. By convention, the sequence of bases in a nucleic acid is usually expressed in the
_________ direction.
A) 3' to 1'
B) 3' to 5'
C) 1' to 3'
D) 5' to 3'
E) clockwise
2. Since the first nucleotides cannot be linked in a newly synthesized strand in DNA
replication, ___________ is required.
A) a DNA primer
B) DNA polymerase
C) ligase
D) an RNA primer
E) helicase
3. Okazaki fragments are used to elongate
A) the leading strand toward the replication fork
B) the lagging strand toward the replication fork
C) both strands in both directions
D) the leading strand away from the replication fork
E) the lagging strand away from the replication fork
4. In nucleic acids, the free hydroxyl group is attached to the _______________ carbon
of the sugar.
A) 5'
B) 4'
C) 3'
D) 2'
E) 1'
5. In DNA guanine always pairs with
A) adenine
B) cytosine
C) guanine
D) thymine
E) uracil
6. In DNA, thymine always pairs with
A) adenine
B) cytosine
C) guanine
D) thymine
E) uracil
7. DNA replication is called semiconservative because _______________ of the original
duplex appears in the duplex formed in replication.
A) none
B) most
C) half
D) hardly any
E) all
8. Each unit of a nucleic acid consisting of a sugar, attached phosphate group, and base is
a
A) nucleolus
B) nucleotide
C) nucleosome
D) histone
E) genetisome
9. In replication of DNA, the helix is opened and untwisted by
A) ribase
B) ligase
C) deoxase
D) helicase
E) polymerase
10. In a nucleic acid, the bases are always attached to the _______________ carbon of
the sugar.
A) 5'
B) 4'
C) 3'
D) 2'
E) 1'
11. In nucleic acids, the phosphate group is attached to the _______________ carbon of
the sugar.
A) 5'
B) 4'
C) 3'
D) 2'
E) 1'
12. _______________ join DNA fragments to the lagging strand.
A) Telomeres
B) Centromeres
C) Helicases
D) Ligases
E) Antiparallel strands
13. DNA polymerase catalyzes the elongation of a DNA strand in the 5'-->3' direction.
A) True
B) False
14. A DNA molecule has the same amount of adenine and thymine.
A) True
B) False
15. An actively dividing bacterial culture is grown in a medium containing radioactive
adenine (A*). After all the adenine is labeled, the bacteria are transferred to a medium
containing nonradioactive adenine (A). Following one round of DNA replication in the
nonradioactive medium, the DNA is analyzed. Which of the following sequences could
represent this DNA?
A) A* A* T T G A* T C
TTAACTAG
B) A* A T T G A* T C
T T A* A* C T A G
C) A A T T G A T C
TTAACTAG
D) A* A* T T G A* T C
T T A* A* C T A* G
16. DNA polymerase uses a nucleoside triphosphate, bearing phosphates on the 5' carbon
to form a phosphodiester linkage to the free 3' hydroxyl group on the end of the DNA
strand it is synthesizing.
A) True
B) False
17. DNA is made up of a phosphate group, an organic base, and:
A) a protein
B) a sugar
C) a molecule of ATP
D) a fat
E) none of the above
18. In the DNA molecule:
A) adenine pairs with thymine
B) guanine pairs with thymine
C) cytosine pairs with thymine
D) adenine pairs with cytosine
E) All of the above are possible.
19. If one side of a DNA molecule contains the following sequence of nucleotides,
AGTCCG, the complementary sequence on the other side would be:
A) GCCTGA
B) AGTCCG
C) TCAGGC
D) CTGAAT
E) none of the above
20. During your summer job at Virotech, you isolate a previously unknown virus.
Analysis of its genome reveals that it is composed of a double stranded DNA molecule
containing 14% T (thymine). Based on this information, what would you predict the %C
(cytosine) to be?
A) 14%
B) 28%
C) 36%
D) 72%
E) Cannot be determined from the information given.
21.DNA replication is called semiconservative because half of each of the two new
strands of DNA is "old" DNA from the original DNA molecule and half is "new" DNA.
A) True
B) False
22. A DNA molecule is a polymer made of subunits called
A) bases
B) amino acids
C) nucleotides
D) nucleic acids
E) pyrimidines
23. Which parts of the DNA molecule can be referred to as the “rungs” of a ladder?
Which parts can be referred to as the uprights or backbone?
24. Given the following sequence, what is the complimentary sequence? Make sure to
write it in the correct orientation (i.e. 5’ to 3’).
5’ – ATGCAGCTATGAC – 3’
25. If you were told that 13.4% of the nucleotides in the mouse genome were guanosine,
what percentage of the genome is adenosine, thymidine, and cytidine?
26. Considering the length of the genome of many eukrayotes, explain why there are
multiple replication bubbles, rather than one long synthesis step.
27. Name 3 important enzymes involved in the formation and stabilization of replication
bubbles, and describe their functions briefly.
28. Outline synthesis of the leading strand during DNA replication. Assume the
replication bubbles are already formed. Draw a sketch to help in your description.
29. Outline synthesis of the lagging strand during DNA synthesis. Assume the replication
bubbles are already formed. Draw a sketch to help in your description.