1. 13
The Molecular Basis of Inheritance

2. Who conducted the X-ray diffraction studies that were key to the discovery of the structure of DNA?
Griffith
Franklin
Meselson and Stahl
Chargaff
McClintock
Answer: B. See Figure 13.6, Concept 13.1
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3. Who conducted the X-ray diffraction studies that were key to the discovery of the structure of DNA?
Griffith
Franklin
Meselson and Stahl
Chargaff
McClintock
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4. How do the leading, and the lagging strands differ?
The leading strand is synthesized in the same direction as the movement of the replication fork, and the lagging strand is synthesized in the opposite direction.
The leading strand is synthesized at twice the rate of the lagging strand.
The leading strand is synthesized in short fragments that are ultimately stitched together, whereas the lagging strand is synthesized continuously.
The leading strand is synthesized by adding nucleotides to the 3′ end of the growing strand, and the lagging strand is synthesized by adding nucleotides to the 5′ end.
Answer: A. See Figures 13.12, 13.15, 13.16, and DNA is made only in the 5′ to 3′ direction.
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5. How do the leading, and the lagging strands differ?
The leading strand is synthesized in the same direction as the movement of the replication fork, and the lagging strand is synthesized in the opposite direction.
The leading strand is synthesized at twice the rate of the lagging strand.
The leading strand is synthesized in short fragments that are ultimately stitched together, whereas the lagging strand is synthesized continuously.
The leading strand is synthesized by adding nucleotides to the 3′ end of the growing strand, and the lagging strand is synthesized by adding nucleotides to the 5′ end.
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6. What enzyme does a gamete-producing cell include that compensates for replication-associated shortening?
DNA polymerase II
ligase
telomerase
DNA nuclease
proofreading enzyme
Answer: C.
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7. What enzyme does a gamete-producing cell include that compensates for replication-associated shortening?
DNA polymerase II
ligase
telomerase
DNA nuclease
proofreading enzyme
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8. Suppose a double-stranded DNA molecule was shown to have 15% adenine bases. What would be the expected percentage of guanine bases in that molecule?
15%
35%
85%
not enough information
Answer: B. This is a simple application of Chargaff′s rule. A = T, so there is 30%. G plus C must make up the remaining 70% in equal proportions.
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9. Suppose a double-stranded DNA molecule was shown to have 15% adenine bases. What would be the expected percentage of guanine bases in that molecule?
15%
35%
85%
not enough information
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10. Consider the replication bubble diagrammed at the right
Consider the replication bubble diagrammed at the right. Which letters represent leading strands?
W and X
Y and Z
W and Z
X and Y 3′ 5′ W Y X Z
Answer: D. This question should uncover many misconceptions about replication. Note the altered 5′ and 3′ orientation from text figures. Replication proceeds 5′→ 3′ in antiparallel fashion.
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11. Consider the replication bubble diagrammed at the right
Consider the replication bubble diagrammed at the right. Which letters represent leading strands?
W and X
Y and Z
W and Z
X and Y 3′ 5′ W Y X Z
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12. Consider the replication bubble diagrammed at the right
Consider the replication bubble diagrammed at the right. Which letters represent where one could find Okazaki fragments? 3′ 5′ W Y X Z
W and X
Y and Z
W and Z
X and Y
Answer: C. This question should uncover many misconceptions about replication. Note the altered 5′ and 3′ orientation from text figures. Replication proceeds 5′→ 3′ in antiparallel fashion.
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13. Consider the replication bubble diagrammed at the right
Consider the replication bubble diagrammed at the right. Which letters represent where one could find Okazaki fragments? 3′ 5′ W Y X Z
W and X
Y and Z
W and Z
X and Y
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14. Consider the replication bubble diagrammed at the right
Consider the replication bubble diagrammed at the right. Which diagram below depicts what this structure would look like when replication is complete? 3′ 5′ 3′ 5′ 3′ 5′
and
Answer: C. C shows completed replication with two daughter molecules, each in antiparallel configuration. A, B, and D indicate misconceptions of varying degrees. 3′ 5′
and
and
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15. Consider the replication bubble diagrammed at the right
Consider the replication bubble diagrammed at the right. Which diagram below depicts what this structure would look like when replication is complete? 3′ 5′ 3′ 5′ 3′ 5′
and 3′ 5′
and
and
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16. Imagine a bacterial cell with a mutation that renders DNA Pol I completely nonfunctional (note that this would be a lethal mutation). What, precisely, would go wrong with replication in this cell?
inability to unwind double helix
inability to prime replication
inability to extend the length of leading and lagging strands
inability to replace primers
Answer: D.
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17. Imagine a bacterial cell with a mutation that renders DNA Pol I completely nonfunctional (note that this would be a lethal mutation). What, precisely, would go wrong with replication in this cell?
inability to unwind double helix
inability to prime replication
inability to extend the length of leading and lagging strands
inability to replace primers
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18. DNA replication overall has very high fidelity
DNA replication overall has very high fidelity. Which of the following phenomena or processes contribute to this high fidelity? More than one may apply.
base pairing
proofreading
mismatch repair
Answer: All apply.
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19. DNA replication overall has very high fidelity
DNA replication overall has very high fidelity. Which of the following phenomena or processes contribute to this high fidelity? More than one may apply.
base pairing
proofreading
mismatch repair
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20. Which of the following would typically not be used to clone DNA?
plasmid vector
telomerase
restriction enzyme
PCR
Answer: B.
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21. Which of the following would typically not be used to clone DNA?
plasmid vector
telomerase
restriction enzyme
PCR
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22. Arrange the following terms in order, from smallest to largest size: nucleosome, metaphase chromosome, histone, 30-nm fiber.
histone, nucleosome, 30-nm fiber, metaphase chromosome
nucleosome, histone, 30-nm fiber, metaphase chromosome
histone, nucleosome, metaphase chromosome, 30-nm fiber
30-nm fiber, histone, nucleosome, metaphase chromosome
Answer: A.
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23. Arrange the following terms in order, from smallest to largest size: nucleosome, metaphase chromosome, histone, 30-nm fiber.
histone, nucleosome, 30-nm fiber, metaphase chromosome
nucleosome, histone, 30-nm fiber, metaphase chromosome
histone, nucleosome, metaphase chromosome, 30-nm fiber
30-nm fiber, histone, nucleosome, metaphase chromosome
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