Question 1

Which of the following best describes the function of telomeres in eukaryotic cells?

Accepted Answer

They act as a buffer to protect protein-coding DNA from being lost during DNA replication.

Question 2

A cell is unable to pass the G1 checkpoint. Which of the following is the most likely reason?

Accepted Answer

The cell size is inadequate or DNA is damaged.

Question 3

Which protein is primarily responsible for halting the cell cycle in response to DNA damage at the G1 checkpoint?

Accepted Answer

p53

Question 4

Why do elephants have a lower cancer rate than humans, despite having many more cells?

Accepted Answer

They have extra copies of the p53 gene, increasing the likelihood of cell death in response to DNA damage.

Question 5

Which of the following events occurs during the S phase of the cell cycle?

Accepted Answer

DNA replication

Question 6

A mutation in the BRCA1 gene increases the risk of cancer because:

Accepted Answer

BRCA1 is involved in DNA repair, and its loss leads to genome instability.

Question 7

Which of the following best explains why telomerase is important in certain cell types?

Accepted Answer

Telomerase restores telomere length, allowing cells to divide beyond the Hayflick limit.

Question 8

A researcher treats cancer cells with Taxol, a drug that destabilizes microtubules. What is the most likely effect on the cell cycle?

Accepted Answer

Cells will arrest at the metaphase checkpoint due to improper spindle attachment.

Question 9

Which of the following is a direct consequence if DNA polymerase fails to proofread during DNA replication?

Accepted Answer

Increased rate of mutations in daughter cells

Question 10

Which checkpoint ensures that all chromosomes are properly attached to the spindle apparatus before proceeding?

Accepted Answer

Metaphase checkpoint

Question 11

A cell is exposed to UV light, resulting in the formation of thymine dimers. Which DNA repair mechanism is most likely to be activated?

Accepted Answer

Nucleotide excision repair

Question 12

Which of the following equations best represents the loss of DNA nucleotides from chromosome ends after each round of DNA replication?

Accepted Answer

$$n_{final} = n_{initial} - 2d$$

Question 13

Which of the following is NOT a requirement for a cell to pass the G1 checkpoint?

Accepted Answer

Activated MPF is present

Question 14

If a cell's telomeres become critically short, what is the most likely outcome?

Accepted Answer

The cell will enter senescence or undergo apoptosis.

Question 15

Which of the following statements about cyclin-dependent kinases (CDKs) is correct?

Accepted Answer

CDKs are always present but require cyclin binding to become active.

Question 16

A patient is diagnosed with a cancer that re-expresses telomerase. What is the most likely effect on the cancer cells?

Accepted Answer

They will maintain telomere length and divide indefinitely.

Question 17

Which of the following best explains why multiple mutations are typically required for a cell to become cancerous?

Accepted Answer

Multiple mutations are needed to bypass all cell cycle checkpoints and evade cell death.

Question 18

Which of the following drugs would most likely inhibit DNA synthesis in rapidly dividing cancer cells?

Accepted Answer

Quinolones

Question 19

During which phase of the cell cycle does MPF (M-phase promoting factor) activity peak?

Accepted Answer

M phase

Question 20

A cell with a mutation in the uvrA gene is exposed to UV light. What is the most likely outcome compared to wild-type cells?

Accepted Answer

The cell will have a decreased survival rate due to impaired DNA repair.

Cell Cycle Regulation, DNA Damage, and Cancer: Foundations of Cellular Biology

Study Guide - Practice Questions