Q: Which of the following equations correctly represents the formation of a phosphodiester bond during DNA synthesis?

$$\text{(dNMP)}_{n} + \text{dNTP} \rightarrow \text{(dNMP)}_{n+1} + \text{PP}_i$$

Question 1

Which of the following best describes the semi-conservative model of DNA replication?

Accepted Answer

Each daughter DNA molecule consists of one parental strand and one newly synthesized strand.

Question 2

During DNA replication, which enzyme is responsible for synthesizing the RNA primer required for DNA polymerase to begin synthesis?

Accepted Answer

Primase

Question 3

What is the main function of single-stranded binding (SSB) proteins during DNA replication?

Accepted Answer

They prevent the re-annealing of separated DNA strands.

Question 4

Which of the following statements about DNA polymerase is FALSE?

Accepted Answer

DNA polymerase can initiate DNA synthesis without a primer.

Question 5

The Meselson-Stahl experiment used isotopes of nitrogen to distinguish between old and new DNA strands. Which result ruled out the conservative model of DNA replication after one round of replication?

Accepted Answer

The appearance of DNA with intermediate density.

Question 6

Which enzyme is responsible for joining Okazaki fragments on the lagging strand during DNA replication?

Accepted Answer

DNA ligase

Question 7

Why is there a 'replication end problem' in eukaryotic linear chromosomes?

Accepted Answer

DNA polymerase requires a free 3’ OH group, which is missing at the very end of the chromosome.

Question 8

What is the role of telomerase in eukaryotic cells?

Accepted Answer

It adds repetitive DNA sequences to the ends of chromosomes.

Question 9

Which of the following best explains why Okazaki fragments are formed during DNA replication?

Accepted Answer

DNA polymerase can only synthesize DNA in the 5’ to 3’ direction, so the lagging strand is synthesized discontinuously.

Question 10

Which of the following equations correctly represents the formation of a phosphodiester bond during DNA synthesis?

Accepted Answer

$$	ext{(dNMP)}_{n} + 	ext{dNTP} ightarrow 	ext{(dNMP)}_{n+1} + 	ext{PP}_i$$

Question 11

A mutation in the gene encoding DNA polymerase’s 3’ to 5’ exonuclease activity would most likely result in which of the following?

Accepted Answer

Increased frequency of replication errors.

Question 12

Which of the following is a property shared by both prokaryotic and eukaryotic DNA polymerases?

Accepted Answer

They both require a primer with a free 3’ OH group.

Question 13

Which of the following best describes the function of topoisomerase during DNA replication?

Accepted Answer

It removes supercoils ahead of the replication fork.

Question 14

In the context of the Meselson-Stahl experiment, what would be the expected result after two rounds of replication if DNA replication were dispersive?

Accepted Answer

All DNA would be of intermediate density.

Question 15

Which of the following is NOT a required property of genetic material?

Accepted Answer

It must be composed of protein.

Question 16

Which of the following statements about telomeres is TRUE?

Accepted Answer

They consist of repetitive, non-coding DNA sequences.

Question 17

Which of the following best explains why the leading strand is synthesized continuously while the lagging strand is synthesized discontinuously?

Accepted Answer

The leading strand template is oriented 3’ to 5’ toward the replication fork, allowing continuous synthesis in the 5’ to 3’ direction.

Question 18

Which of the following is the correct sequence of events during the initiation of E. coli DNA replication?

Accepted Answer

Helicase unwinds DNA, SSB proteins bind, primase synthesizes primer, DNA polymerase III extends DNA.

DNA Replication: Mechanisms, Enzymes, and Experimental Evidence

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