Question 1

Which statement best describes the semiconservative 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 short RNA primers on the lagging strand?

Accepted Answer

Primase

Question 3

What is the direction of DNA synthesis by DNA polymerase?

Accepted Answer

DNA is synthesized in the $$5' \rightarrow 3'$$ direction.

Question 4

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

Accepted Answer

DNA polymerase can only synthesize DNA in the $$5' \rightarrow 3'$$ direction, so the lagging strand is synthesized discontinuously.

Question 5

Which enzyme is responsible for joining Okazaki fragments together on the lagging strand?

Accepted Answer

DNA ligase

Question 6

What is the role of DNA helicase during DNA replication?

Accepted Answer

It unwinds the DNA double helix at the replication fork.

Question 7

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

Accepted Answer

It relieves torsional stress by creating transient single-strand breaks, allowing free rotation of DNA.

Question 8

During DNA replication, what is released as a byproduct when a nucleoside triphosphate is added to the growing DNA strand?

Accepted Answer

A pyrophosphate ($$PP_i)$$

Question 9

Which of the following mechanisms ensures high fidelity during DNA replication?

Accepted Answer

DNA polymerase proofreading activity

Question 10

A mutation disables the exonuclease activity of DNA polymerase. What is the most likely consequence?

Accepted Answer

The error rate during DNA replication will increase.

Question 11

Which of the following is true regarding the origin of replication in eukaryotic cells?

Accepted Answer

Multiple origins of replication exist on each chromosome.

Question 12

What is the function of the sliding clamp during DNA replication?

Accepted Answer

It increases the processivity of DNA polymerase by holding it onto the DNA.

Question 13

Which of the following best explains why DNA polymerase cannot initiate synthesis of a new DNA strand by itself?

Accepted Answer

It requires a free $$3'-OH $$group provided by an RNA primer.

Question 14

A patient has a genetic defect in DNA ligase. Which cellular process would be most directly affected?

Accepted Answer

Joining of Okazaki fragments on the lagging strand during DNA replication

Question 15

Which of the following sequences is most likely to be found at the origin of replication in DNA?

Accepted Answer

A region rich in AT base pairs

Question 16

Which enzyme is responsible for removing RNA primers during DNA replication?

Accepted Answer

Exonuclease

Question 17

In a cell lacking functional topoisomerase, what would most likely happen during DNA replication?

Accepted Answer

Torsional stress would build up, potentially halting replication.

Question 18

Which of the following best describes the role of telomerase in eukaryotic cells?

Accepted Answer

It extends the $$3'$$ end of the lagging strand template to prevent chromosome shortening.

Question 19

A scientist observes that a cell has a high rate of mutations after DNA replication. Which process is most likely defective?

Accepted Answer

Mismatch repair

Question 20

Which of the following equations correctly represents the addition of a nucleoside triphosphate to a growing DNA strand?

Accepted Answer

$$(DNA)_{n} + dNTP \rightarrow (DNA)_{n+1} + PP_i$$

DNA Replication: Mechanisms and Molecular Details

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