Question 1

Which of the following best describes the semiconservative model of DNA replication?

Accepted Answer

Each new DNA molecule consists of one original strand and one new strand.

Question 2

During DNA replication, which enzyme is responsible for relieving the tension caused by unwinding the DNA helix?

Accepted Answer

Topoisomerase

Question 3

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

Accepted Answer

They hold the two parent DNA strands apart to prevent re-annealing.

Question 4

Which of the following statements about the leading and lagging strands during DNA replication is correct?

Accepted Answer

The leading strand is synthesized continuously toward the replication fork, while the lagging strand is synthesized discontinuously away from the fork.

Question 5

Which enzyme removes RNA primers and replaces them with DNA during lagging strand synthesis?

Accepted Answer

DNA polymerase I

Question 6

A mutation causes a cell to lack functional primase. What is the most likely outcome during DNA replication?

Accepted Answer

No RNA primers are synthesized, so DNA polymerase cannot initiate synthesis.

Question 7

Which of the following is NOT a component of a DNA nucleotide?

Accepted Answer

A ribose sugar

Question 8

According to Chargaff's rules, if a DNA sample contains 30% adenine, what percentage of guanine would you expect?

Accepted Answer

20%

Question 9

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

Accepted Answer

DNA ligase

Question 10

What is the main function of telomeres in eukaryotic chromosomes?

Accepted Answer

They postpone the erosion of genes at chromosome ends.

Question 11

Which direction does DNA polymerase synthesize new DNA?

Accepted Answer

5' to 3'

Question 12

Which of the following best explains why eukaryotic chromosomes have multiple origins of replication?

Accepted Answer

To speed up the copying of long DNA molecules.

Question 13

What is the role of nucleotide excision repair in DNA replication?

Accepted Answer

It removes incorrect nucleotides and replaces them with correct ones.

Question 14

Which of the following is a correct description of an Okazaki fragment?

Accepted Answer

A short segment of DNA synthesized on the lagging strand.

Question 15

If the sequence of one DNA strand is 5'-ATCGGTA-3', what is the sequence of the complementary strand?

Accepted Answer

3'-TAGCCAT-5'

Question 16

Which enzyme is responsible for synthesizing the RNA primer during DNA replication?

Accepted Answer

Primase

Question 17

What would happen if telomerase was not active in germ cells?

Accepted Answer

Telomeres would shorten with each cell division, potentially leading to loss of genetic information.

Question 18

Which of the following equations correctly represents the relationship between purines and pyrimidines in DNA according to Chargaff's rules?

Accepted Answer

$$A + G = T + C$$

Question 19

During DNA replication, which process is exergonic and provides energy for polymerization?

Accepted Answer

Hydrolysis of two phosphate groups from each dNTP

Question 20

A cell is found to have a high rate of DNA errors after replication. Which enzyme is most likely defective?

Accepted Answer

DNA polymerase III

DNA Replication: Structure, Mechanism, and Enzymatic Function

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