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

A mutation causes the loss of function of the SSBP (single-strand binding proteins) during DNA replication. What is the most likely consequence?

Accepted Answer

Single-stranded DNA will re-anneal or form secondary structures, impeding replication

Question 4

Which of the following best explains why the lagging strand is synthesized discontinuously during DNA replication?

Accepted Answer

DNA polymerase can only add nucleotides in the 5' to 3' direction, so the lagging strand must be synthesized in short fragments as the fork opens

Question 5

During which phase of the cell cycle does DNA replication occur?

Accepted Answer

S phase

Question 6

A cell is observed to have a damaged nuclear envelope. Which of the following processes would be most directly affected?

Accepted Answer

Regulation of transport between the nucleus and cytoplasm

Question 7

Which enzyme is responsible for joining Okazaki fragments on the lagging strand during DNA replication?

Accepted Answer

Ligase

Question 8

A patient is diagnosed with a mutation that prevents the G1 checkpoint from functioning. What is the most likely result?

Accepted Answer

Cells may proceed to DNA synthesis with damaged or incomplete DNA, increasing the risk of cancer

Question 9

Which of the following correctly matches the enzyme to its function during DNA replication?

Accepted Answer

Helicase: Unwinds the DNA double helix at the replication fork

Question 10

During which stage of mitosis do sister chromatids separate and move toward opposite poles?

Accepted Answer

Anaphase

Question 11

Which of the following best describes the role of histone proteins in the cell nucleus?

Accepted Answer

They package and organize DNA into structural units called nucleosomes

Question 12

A scientist is studying the process of transcription. Which of the following is the correct sequence of the three main events in mRNA formation?

Accepted Answer

Initiation, elongation, termination

Question 13

If a cell's DNA polymerase is inhibited, which of the following processes will be directly affected?

Accepted Answer

Synthesis of new DNA strands during replication

Question 14

Which of the following equations correctly represents the semi-conservative model of DNA replication?

Accepted Answer

$DNA_{parental} \rightarrow DNA_{daughter1} + DNA_{daughter2}$, where each daughter contains one parental and one new strand

Question 15

A researcher observes that after mitosis, two daughter cells are produced, each with the same number of chromosomes as the original cell. Which phase ensures this equal distribution?

Accepted Answer

Anaphase

Question 16

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 direction of the replication fork, while the lagging strand is synthesized discontinuously away from the fork

Question 17

During which phase of the cell cycle does the G2 checkpoint occur, and what is its primary function?

Accepted Answer

G2 phase; to ensure DNA has been accurately replicated before mitosis

Question 18

A cell is exposed to a chemical that inhibits helicase activity. What is the most immediate effect on DNA replication?

Accepted Answer

The DNA double helix will not be unwound, preventing replication from proceeding

Question 19

Which of the following best describes the function of a primer during DNA replication?

Accepted Answer

It provides a free 3'-OH group for DNA polymerase to begin synthesis

Question 20

A patient is found to have a defect in the nuclear envelope. Which of the following cellular processes is most likely to be disrupted as a result?

Accepted Answer

Transport of mRNA from the nucleus to the cytoplasm

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

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