Question 1

Which of the following best describes the structure of a nucleosome in eukaryotic chromatin?

Accepted Answer

A segment of DNA wrapped around a core of eight histone proteins

Question 2

During DNA replication, which enzyme is responsible for relieving the tension ahead of the replication fork by cutting and rejoining DNA strands?

Accepted Answer

Topoisomerase

Question 3

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

Accepted Answer

The leading strand is synthesized continuously in the 5' to 3' direction, while the lagging strand is synthesized discontinuously as Okazaki fragments.

Question 4

A mutation causes the loss of function of DNA ligase during replication. Which of the following would most likely occur as a result?

Accepted Answer

Okazaki fragments on the lagging strand would remain unjoined, resulting in incomplete DNA synthesis.

Question 5

Which checkpoint in the cell cycle ensures that DNA is undamaged and fully replicated before the cell enters mitosis?

Accepted Answer

G2 checkpoint

Question 6

During which phase of mitosis do sister chromatids separate and move toward opposite poles of the cell?

Accepted Answer

Anaphase

Question 7

Which enzyme synthesizes the RNA primer required for DNA polymerase to begin DNA synthesis?

Accepted Answer

Primase

Question 8

A scientist observes that a cell is unable to separate its nuclear envelope during mitosis. Which stage is most likely affected?

Accepted Answer

Prophase

Question 9

Which of the following best describes the role of single-strand binding proteins (SSBP) during DNA replication?

Accepted Answer

They stabilize unwound DNA strands and prevent them from re-annealing.

Question 10

During transcription, which of the following events occurs first?

Accepted Answer

RNA polymerase binds to the promoter region of DNA.

Question 11

A patient is diagnosed with a mutation that prevents the formation of histone proteins. Which of the following consequences is most likely?

Accepted Answer

DNA would not be able to efficiently compact into chromatin, leading to problems with gene regulation.

Question 12

Which of the following equations correctly represents the number of DNA molecules present after $n$ rounds of replication, starting from a single DNA molecule?

Accepted Answer

$2^n$

Question 13

Which of the following is NOT a function of the nuclear envelope?

Accepted Answer

Synthesizing ribosomal RNA

Question 14

During the S phase of the cell cycle, which of the following processes occurs?

Accepted Answer

DNA is replicated, resulting in two identical sister chromatids for each chromosome.

Question 15

Which of the following best explains why the lagging strand is synthesized in short fragments during DNA replication?

Accepted Answer

DNA polymerase can only add nucleotides in the 5' to 3' direction, so the lagging strand must be synthesized away from the replication fork in segments.

Question 16

A cell is observed to have chromosomes aligned at the center of the cell, attached to spindle fibers. Which phase of mitosis is this?

Accepted Answer

Metaphase

Question 17

Which of the following is the correct sequence of events during transcription?

Accepted Answer

Initiation, elongation, termination

Question 18

If a mutation prevents the function of helicase during DNA replication, what is the most likely outcome?

Accepted Answer

The DNA double helix would not unwind, preventing replication from proceeding.

Question 19

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

Accepted Answer

It adds nucleotides to the growing DNA strand in the 5' to 3' direction.

Question 20

A researcher is studying the process of mRNA formation. Which of the following is NOT a main event of transcription?

Accepted Answer

Attachment of ribosomes to mRNA

DNA Structure, Replication, Mitosis, and Transcription: Study Guide

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