1. If you could pick up a single chromosome in your hand, what types of macromolecules
would you be holding?
A.
B.
C.
D.
E.
DNA
protein
RNA
b&c
a,b,&c*
2. Nucleotides on a single-stranded DNA molecule are connected by:
A.
B.
C.
D.
E.
chromosomes
nucleosides
nucleotides
phosphodiester bonds*
proteins
3. The polarity of DNA synthesis is
A.
B.
C.
D.
3'-->5'
5'-->2'
5'-->3' *
None of the choices is correct.
4. The ratio of adenine to thymine in naturally-occuring DNA __________, while the ratio of
adenine to cytosine __________.
A.
B.
C.
D.
E.
is 1:1; is 1:1
is 1:1; varies *
varies; is 1:1
varies; varies
none of the above
5. ________ bonds are used to hold consecutive nucleotides together in each single strand
of DNA, while ________ bonds are used for complementary base pairing in DNA.
A.
B.
C.
D.
E.
covalent; hydrogen *
covalent; ionic
hydrogen; covalent
ionic; hydrogen
none of the above
6. A nucleotide is composed of:
A.
B.
C.
D.
E.
base
phosphate
sugar
a&b
a,b,&c*
7. If 30% of the bases in a region of the mouse genome are cytosine, what percentage in that
region are adenine?
A. 20% *
B. 30%
C. 40%
D. 50%
E. 60%
F.
Chapter 6 Homework part 1
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8. The complementary sequence of 5'-AGGGTCTCGA- 3' is:
A.
B.
C.
D.
E.
5'- ACCCTCTCGA- 3'
5'- AGCTCTCCCA - 3'
5'- TCCCAGAGCT - 3'
5'- TCGAGACCCT - 3'*
none of the above
9. In Griffith's 1928 experiment demonstrating bacterial transformation, injection of live S
bacteria resulted in ________ mice, injection of live R bacteria resulted in ________ mice,
and simultaneous injection of heat-killed S cell components and live R bacteria resulted in
________ mice.
A.
B.
C.
D.
E.
dead; dead; dead
dead; dead; live
dead; live; dead*
dead; live; live
live; dead; live
10. In 1944, Avery, MacLeod, and McCarty extended Griffith's experiments by showing that the
transformation activity of the "transforming principle" was inactivated by __________.
A.
B.
C.
D.
E.
DNase *
Protease
RNase
ultracentrifugation
b&c
11. In the Hershey and Chase experiment designed to determine the molecule of heredity,
what was radiolabeled with 35S?
A.
B.
C.
D.
protein *
DNA
RNA
None of these choices are correct.
12. In the Hershey and Chase experiment designed to determine the molecule of heredity,
what was radiolabeled with 32P?
A.
B.
C.
D.
E.
protein
DNA *
RNA
rRNA
a&b
13. To help elucidate the double helix structure of DNA, __________ used information provided
by __________ that certain bases are always present in a 1:1 ratio.
A.
B.
C.
D.
E.
Meselson and Stahl; Chargaff
Watson and Crick; Chargaff*
Watson and Crick; Franklin
Watson and Crick; Meselson and Stahl
none of the above
Chapter 6 Homework part 1
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14. Replication of the Escherichia coli genome begins from ____ origin(s) of replication.
A.
B.
C.
D.
E.
an unidirectional
many
one*
several
two
15. During DNA synthesis, the leading strand is synthesized _______ and the lagging strand is
synthesized ________.
A.
B.
C.
D.
3' to 5'; 3' to 5'
3' to 5'; 5' to 3'
5' to 3'; 3' to 5'
5' to 3'; 5' to 3'*
16. The Meselson and Stahl experiment used a non-radioactive rare isotope of nitrogen to
identify newly replicated DNA. The outcome of this experiment supported the
__________model of DNA replication.
A.
B.
C.
D.
E.
conservative
dispersive
semiconservative*
transferal
none of the above
17. Meselson and Stahl allowed bacteria raised in 15N medium to replicate in 14N media. At the
end of two rounds of DNA replication in 14N media, they observed ______ band(s) in their
centrifugation tubes. These band(s) was/were composed of _______.
A.
B.
C.
D.
E.
one; a single strand of 15N DNA base-paired to single strand of 14N DNA
one; double stranded DNA, each strand made up of a mixture of 14N and 15N DNA
two; double stranded DNA, the upper band was pure 14N DNA and the lower band was pure 15N
DNA
two; double stranded DNA, the upper band was pure 14N DNA and the lower band was made of DNA
in which one strand was 15N DNA and the other strand was 14N DNA*
two; double stranded DNA, the upper band was made of DNA in which one strand was 15N DNA and
the other strand was 14N DNA and the lower band was 15N DNA
18. In the Meselson and Stahl experiment, if DNA replication had been conservative, after one
round of replication in the 14N media they would have observed _________ in the
centrifuge tube.
A.
B.
C.
D.
E.
one heavy band (pure 15N DNA)
one intermediate weight band (half 14N and half 15N DNA)
two bands, one heavy (pure 15N DNA) and one intermediate (half 14N and half 15N DNA)
two bands, one heavy (pure 15N DNA) and one light (pure 14N DNA)*
two bands, one intermediate (half 14N and half 15N DNA) and one light (pure 14N DNA)
Chapter 6 Homework part 1
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19. Match each item in the left column with the most appropriate description in the right
column. Each letter in the right column should be used once and only once.
1. cellular DNA ligase *F*
[A} a DNA-dependent RNA polymerase
2. DNA polymerase III *C*
[B} an intermediate found on the lagging
strand of DNA synthesis
3. DNA template *G*
[C] catalyzes linkage of one
deoxyribonucleotide to another
4. helicase *J*
[D] DNA sequence where replication begins
5. lagging strand *E*
[E] is synthesized discontinuously
6. leading strand *I*
[F] joins consecutive DNA fragments together
if base-paired to a template and if separated
by only one missing phosphodiester bond
7. Okazaki fragments *B*
[G] read by DNA polymerase to synthesize a
strand of DNA
8. origin of replication *D*
[H] relieves tension as helix is unwound during
replication
9. primase *A*
[I] synthesized as a continuous strand
10. topoisomerase *H*
[ J ] unwinds strands at replication fork
A.
[A][G][F][D][B][ I ][C][ J ][E][H]
B.
[C][B][F][A][G][D][ I ][E][H][ J ]
C.
[C][G][F][ I ][ J ][E][B][H][D][A]
D.
[C][G][F][E][ I ][ J ][B][D][H][A]
E.
[F][A][G][D][ I ][C][B][E][H][ J ]
F.
[F][C][G][ J ][E][ I ][B][D][A][H]*
G.
[G][H][E][D][F][ J ][A][ I ][C][B]
H.
[H][C][B][F][A][ I ][E][ J ][G][D]
I.
[H][E][ J ][G][D][C][B][F][A][ I ]
J.
[H][E][D][G][C][F][A][ I ][ J ][B]
Chapter 6 Homework part 1
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20. Match the scientists with their contribution to understanding the structure of DNA.
1. did a famous phage blender experiment
*D*
[A] Avery, MacLeod, and McCarty
2. first proposed the correct structure of DNA [B] Chargaff
*E*
3. repeated Griffiths work in vitro and clearly. [C] Griffith
showed that DNA was the molecule of heredity
*A*
4. first to transform bacteria and to use the
term transformation *C*
[D] Hershey and Chase
5. Maurice Wilkins *H*
[E] James Watson and Francis Crick
6. nucleotide ratios in DNA *B*
[F] Meselson and Stahl
7. performed the extremely high quality X-ray [G] Rosalind Franklin
diffraction experiments that were used to
solve the structure of DNA *G*
8. showed that bacterial genomes replicated
using by semiconservative replication *F*
A.
[A} [H] [D] [E] [G] [C] [F] [B]
B.
[D] [C] [H] [A} [E] [G] [B] [F]
C.
[D] [E] [A} [C] [H] [B] [G] [F]*
D.
[D] [E] [A} [H] [C] [B] [F] [G]
E.
[D] [H] [C] [B] [F] [A} [E] [G]
F.
[E] [D] [A} [C] [H] [B] [G] [F]
G.
[H] [A} [E] [D] [C] [G] [B] [F]
H.
[H] [C] [B] [F] [G] [D] [E] [A}
[H] worked on the x-diffraction of DNA fibers
21. The DNA double helix makes one turn every __________ nm. There are ____ nucleotides
per turn of the helix and the helix has a diameter of ________ nm.
A.
B.
C.
D.
10, 8, 20
3.4, 10, 2*
34, 10, 2
34, 10, 20
22. In equilibrium density gradient centrifugation, DNA forms bands because
A.
B.
C.
D.
DNA molecules will associate with one another because of intramolecular base pairing. While this is
rare only one is needed to cause two DNA molecules to associate.
the DNA is being pelleted to the bottom of the centrifuge tube and a rarely-seen intermediate in
centrifugal pelleting is a band.
the pore size in the gel retards the migration of the DNA so that it forms a band at the position of its
molecular weight
the solution below the DNA is more dense than the DNA and the solution above the DNA is less dense
than the DNA*
Chapter 6 Homework part 1
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23. Meselson and Stahl relied on equilibrium density gradient centrifugation in a _______
solution to resolve the DNA containing 14N from DNA containing 15N.
A.
B.
C.
D.
E.
calcium chloride
cesium chloride*
radiolabeled nitrogen
radiolabeled phosphate
sodium acetate
24. Hershey and Chase relied on ________ to physically separate the infected bacterial cells
from the phage ghosts.
A.
B.
C.
D.
E.
centrifugation*
gel filtration
ion exchange
radioactivity
None of the choices is correct.
25. In the Hershey and Chase experiment, phage ghosts are what?
A.
B.
C.
D.
Fantasmas that haunt bacterial colonies.
Newly synthesized phage inside the bacterial cell that appear just before phage lysis.
Phage genomes that are missing the surrounding protein coat.
Phage missing their genetic information*
26. The complementary sequence of 5' AATTCGCTTA 3' is
A.
B.
C.
D.
E.
3'
3'
5'
5'
5'
AATTCGCTTA 5'
TAAGCGAATT 5'
AATTCGCTTA 3'
TAACGCTTAA 3'
TAAGCGAATT 3'*
27. If 35% of the bases in a region of the mouse genome are cytosine, what percentage in that
region are adenine?
A.
B.
C.
D.
E.
15% *
20%
30%
35%
It is not possible to determine the answer from the information that has been provided.
28. What radiolabeled substance did Hershey and Chase use to label the protein component of
the bacteriophage in their study to determine whether protein or DNA was necessary for
phage reproduction?
A.
B.
C.
D.
E.
carbon
iodide
nitrogen
phosphorus
sulfur*
Chapter 6 Homework part 1
6
29. Which were the radioactive isotopes used by Hershey and Chase in their historic
experiment that showed that DNA was is the genetic material?
A.
B.
C.
D.
32
S
S
35
S
35
S
32
and
and
and
and
31
P
P
31
P
32
P*
32
30. During the S phase of interphase, the state of the DNA in a chromosome can be described
as _______________________
A.
B.
C.
D.
E.
a double helix that is replicating conservatively.
a double helix that is replicating semiconservatively. *
a single continuous double helix.
a triple helix that is replicating semiconservatively.
None of the choices are correct.
31. During the G1 phase of interphase, the state of the DNA in a chromosome can be
described as
A.
B.
C.
D.
E.
a double helix that is replicating conservatively.
a double helix that is replicating semiconservatively.
a single continuous double helix. *
a triple helix that is replicating semiconservatively.
None of the choices is correct.
32. DNA replication occurs through a _________process.
A.
B.
C.
D.
E.
conservative
dispersive
semiconservative*
transferal
None of the choices is correct.
33. The beta form of DNA is a
A.
B.
a right handed helix *
a left handed helix
34. A phosphodiester bond joins one nucleotide to another in the DNA polymer.
A.
B.
TRUE *
FALSE
35. Pyrimidines are a nitrogenous base containing a double ring, while purines contain a
single ring.
A.
B.
36.
TRUE
FALSE*
Prokaryotes have a circular chromosome surrounded by a nuclear membrane.
A.
B.
TRUE
FALSE*
37. Transformation in bacteria results from the uptake of foreign DNA.
A.
B.
TRUE*
FALSE
Chapter 6 Homework part 1
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38. Alternative resolutions of the Holliday intermediate are responsible for whether or not
crossing over occurs or gene conversion occurs.
A.
B.
TRUE *
FALSE
39. Human DNA is replicated in a conservative manner.
A.
B.
TRUE
FALSE*
40. In cells, DNA is replicated by continuous replication. Another way to ask this is : Do cells
replicate their nuclear genome by continuous replication?
A.
B.
TRUE
FALSE*
41. In semiconservative replication, each strand of the parent molecule can be found in its
entirety in the offspring molecules.
A.
B.
TRUE*
FALSE
42. I have invented an antibiotic that inhibits bacterial cellular ligase. How is DNA replication
affected?
A.
B.
C.
D.
Primers for DNA replication are no longer produced.
Proof reading stops.
The discontinous fragments on the lagging strand of synthesis cannot be joined together.*
The leading strand cannot continue once the RNA primer is removed because the fragments cannot
be processed.
43. Which is the best description of most of the DNA in a cell?
A.
B.
C.
D.
a left-handed double helix in the B conformation
a right-handed double helix in the B conformation *
both right- and left-handed double helixes in the B conformation
Three forms exist. They are A, B, and Z. However, A and Z are used for the spaces between genes.
Chapter 6 Homework part 1
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