Question 1

Which model of DNA replication is supported by experimental evidence and explains that each daughter DNA molecule consists of one parental and one newly synthesized strand?

Accepted Answer

Semiconservative

Question 2

During DNA replication, which enzyme is responsible for unwinding the double helix at the replication fork?

Accepted Answer

Helicase

Question 3

Okazaki fragments are formed on which strand during DNA replication, and why?

Accepted Answer

Lagging strand, because it is synthesized discontinuously in the 5' to 3' direction

Question 4

Which enzyme synthesizes the short RNA primers required for DNA polymerase to begin synthesis on the lagging strand?

Accepted Answer

RNA primase

Question 5

A virus is found to have a genome with 30% G, 30% C, 20% U, and 20% T. What does this suggest about the nature of its genetic material?

Accepted Answer

It is a single-stranded nucleic acid with both DNA and RNA characteristics

Question 6

Which enzyme is responsible for sealing the nicks between Okazaki fragments during DNA replication?

Accepted Answer

DNA ligase

Question 7

In prokaryotic DNA replication, which enzyme is primarily responsible for removing RNA primers and filling in the resulting gaps with DNA?

Accepted Answer

DNA polymerase I

Question 8

Which of the following best describes the directionality of DNA synthesis by DNA polymerases?

Accepted Answer

5' to 3' direction only

Question 9

What is the main function of single-strand binding proteins during DNA replication?

Accepted Answer

To prevent the rewinding of DNA strands

Question 10

Which of the following statements correctly distinguishes prokaryotic from eukaryotic DNA replication?

Accepted Answer

Prokaryotes have a single origin of replication per chromosome

Question 11

A mutation in the gene encoding DNA polymerase III in E. coli results in loss of proofreading activity. What is the most likely consequence?

Accepted Answer

Increased rate of mutations during DNA replication

Question 12

Which of the following best explains why leading and lagging strands exist during DNA replication?

Accepted Answer

DNA polymerase can only synthesize DNA in the 5' to 3' direction

Question 13

During DNA replication, which enzyme relieves the tension caused by unwinding of the DNA helix ahead of the replication fork?

Accepted Answer

Topoisomerase

Question 14

Which of the following is the main enzyme responsible for the synthesis of new DNA strands during prokaryotic DNA replication?

Accepted Answer

DNA polymerase III

Question 15

A patient is diagnosed with a genetic disorder that affects the function of DNA ligase. Which of the following cellular processes would be most directly impaired?

Accepted Answer

Joining of Okazaki fragments on the lagging strand

Question 16

Which of the following best describes the role of RNA in DNA replication?

Accepted Answer

RNA is synthesized as a primer to provide a 3' end for DNA polymerase

Question 17

If DNA polymerase III could add nucleotides in the 3' to 5' direction, which of the following would be true?

Accepted Answer

There would be no need for Okazaki fragments

Question 18

Which of the following equations correctly represents the base pairing in double-stranded DNA?

Accepted Answer

$[A] = [T]$ and $[G] = [C]$

Question 19

A scientist is studying a prokaryotic cell and observes that DNA replication is occurring at a single location on the chromosome. Which feature of prokaryotic DNA replication does this observation illustrate?

Accepted Answer

Single origin of replication

Question 20

Which of the following best explains why DNA polymerase requires a primer to initiate DNA synthesis?

Accepted Answer

DNA polymerase can only add nucleotides to an existing 3' hydroxyl group

DNA Replication: Mechanisms, Enzymes, and Strand Synthesis

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