Question 1

Which enzyme is primarily responsible for synthesizing new DNA strands during DNA replication in prokaryotes?

Accepted Answer

DNA Polymerase III

Question 2

During DNA replication, in which direction is the new DNA strand synthesized?

Accepted Answer

From 5' to 3'

Question 3

What is the function of primase during DNA replication?

Accepted Answer

It synthesizes a short RNA primer to provide a starting point for DNA polymerase

Question 4

Why is an RNA primer necessary for DNA polymerase to begin synthesis of a new DNA strand?

Accepted Answer

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

Question 5

Which of the following best describes the role of DNA polymerase III in prokaryotic DNA replication?

Accepted Answer

It synthesizes the leading and lagging DNA strands by adding nucleotides to the 3' end

Question 6

If a mutation prevents primase from functioning, what would be the immediate effect on DNA replication?

Accepted Answer

No RNA primers would be made, so DNA polymerase could not initiate DNA synthesis

Question 7

Which statement correctly explains why DNA polymerase can only synthesize DNA in the 5' to 3' direction?

Accepted Answer

Because nucleotides can only be added to the free 3' hydroxyl group of the growing strand

Question 8

In the context of DNA replication, what is the function of the RNA primer after DNA synthesis is complete?

Accepted Answer

It is removed and replaced with DNA nucleotides

Question 9

A scientist is studying a new drug that inhibits the activity of DNA polymerase III. Which of the following would most likely be observed in cells treated with this drug?

Accepted Answer

Accumulation of RNA primers without elongation of DNA strands

Question 10

Which of the following best represents the sequence of events during the initiation of DNA replication?

Accepted Answer

Helicase unwinds DNA, primase synthesizes RNA primer, DNA polymerase III extends DNA from primer

Question 11

Suppose a mutation causes DNA polymerase III to add nucleotides in the 3' to 5' direction. What would be the most likely consequence?

Accepted Answer

DNA replication would not occur because nucleotides cannot be added to the 5' end

Question 12

During DNA replication, which strand is synthesized continuously and which is synthesized in fragments?

Accepted Answer

Leading strand is continuous; lagging strand is in fragments

Question 13

Which of the following equations correctly represents the directionality of DNA synthesis?

Accepted Answer

$$5' \rightarrow 3'$$

Question 14

A patient is found to have a genetic disorder in which their cells cannot convert RNA primers into DNA. Which enzyme is most likely defective?

Accepted Answer

DNA polymerase I

Question 15

If the template DNA strand has the sequence 3'-TACGGT-5', what is the sequence of the newly synthesized DNA strand?

Accepted Answer

5'-ATGCCA-3'

DNA Replication: Enzymes and Mechanisms

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