Question 1

Which of the following best explains the role of telomeres in the cell cycle?

Accepted Answer

Telomeres act as a buffer to protect protein-coding DNA from loss during DNA replication.

Question 2

A cell is exposed to UV radiation, resulting in DNA damage. Which checkpoint is most likely to prevent this cell from dividing?

Accepted Answer

G1 checkpoint

Question 3

Which protein is directly responsible for signaling a cell to stop division if DNA damage is detected?

Accepted Answer

p53

Question 4

Why do elephants have a lower cancer rate compared to humans, despite having more cells?

Accepted Answer

Elephants have extra copies of the p53 gene, enhancing DNA damage response.

Question 5

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

Accepted Answer

S phase

Question 6

A drug inhibits DNA polymerase activity. What is the most likely effect on the cell cycle?

Accepted Answer

Cells will fail to pass the G2 checkpoint because DNA replication is incomplete.

Question 7

Which of the following is required for a cell to pass the G1 checkpoint?

Accepted Answer

Adequate cell size, sufficient nutrients, social signals, and undamaged DNA

Question 8

What is the function of cyclin-dependent kinases (CDKs) in the cell cycle?

Accepted Answer

CDKs are only active when bound to cyclin, promoting progression through the cell cycle.

Question 9

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

Accepted Answer

The cell will fail the G1 checkpoint and stop dividing to prevent loss of protein-coding DNA.

Question 10

Which of the following best describes the role of MPF (M-phase promoting factor) in the cell cycle?

Accepted Answer

MPF initiates mitosis by phosphorylating target proteins when cyclin levels are high.

Question 11

A mutation in the gene encoding for a mismatch repair protein would most likely result in:

Accepted Answer

Accumulation of mutations due to failure to correct replication errors.

Question 12

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

Accepted Answer

Metaphase checkpoint

Question 13

Which of the following is a real-world application of telomerase activity?

Accepted Answer

Increasing telomerase expression in mice can improve health and lifespan.

Question 14

A cancer cell is found to have mutations that allow it to move to other tissues. This property is known as:

Accepted Answer

Metastasis

Question 15

Which equation best represents the average number of times a normal human cell can divide before telomeres are depleted?

Accepted Answer

$$N = \frac{L_0$}{r}$$, where $$N is $$the number of divisions, $$L_0 is $$initial telomere length, and $$r is $$the rate of shortening per division.

Question 16

Which of the following is NOT checked at the G1 checkpoint?

Accepted Answer

Spindle attachment

Question 17

A cell with a mutation in the gene for cyclin cannot produce cyclin proteins. What is the most likely consequence?

Accepted Answer

The cell will fail to activate CDKs and will not progress through the cell cycle.

Question 18

Which of the following treatments targets cancer by disrupting DNA synthesis?

Accepted Answer

Drugs that inhibit DNA polymerase, such as Norofloxacin and Ciprofloxacin.

Question 19

If a cell fails the metaphase checkpoint, what is the most likely reason?

Accepted Answer

Chromosomes are not properly attached to the spindle apparatus.

Question 20

Which of the following statements about cancer is correct?

Accepted Answer

Cancer is a disease of the cell cycle, often resulting from mutations that bypass checkpoints.

Cell Cycle and Its Regulation: Study Notes for General Biology

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