Question 1

A mutation causes the CAK gene to be non-functional in a human cell. What is the most immediate effect on the cell cycle?

Accepted Answer

The cyclin-Cdk complex forms but remains only partly active, preventing the cell from passing the G2 to M checkpoint.

Question 2

Which of the following best describes the role of cohesin proteins during mitosis?

Accepted Answer

They hold sister chromatids together until anaphase.

Question 3

A researcher observes that a cell has 46 chromosomes, each consisting of two sister chromatids. In which phase of the cell cycle is this cell most likely found?

Accepted Answer

G2 phase

Question 4

Which checkpoint ensures that all chromosomes are properly attached to spindle fibers before the cell proceeds to anaphase?

Accepted Answer

Metaphase (M) checkpoint

Question 5

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

Accepted Answer

To add phosphate groups to target proteins, regulating cell cycle progression

Question 6

A cell is exposed to a chemical that prevents the degradation of cyclin after mitosis. What is the most likely consequence?

Accepted Answer

The cell will continuously pass through the cell cycle without proper regulation.

Question 7

Which of the following best explains why cancer cells often form tumors?

Accepted Answer

They lose density-dependent inhibition and continue dividing even when crowded.

Question 8

During which phase of the cell cycle does DNA replication occur, and what is the result?

Accepted Answer

S phase; the amount of DNA doubles from $$x to$$ $$2x.$$

Question 9

Which of the following is a direct result of separase activity during anaphase?

Accepted Answer

Cohesin proteins are cleaved, allowing sister chromatids to separate.

Question 10

A scientist observes that a cell has exited the cell cycle and is not preparing to divide. In which state is this cell most likely found?

Accepted Answer

G0 phase

Question 11

Which of the following best describes the relationship between cyclin concentration and MPF activity?

Accepted Answer

MPF activity rises and falls in direct correlation with cyclin concentration.

Question 12

Which of the following scenarios would most likely result in a failure to pass the G1 checkpoint?

Accepted Answer

The cell has insufficient nutrients and damaged DNA.

Question 13

Which of the following is a real-world example of a growth factor influencing the cell cycle?

Accepted Answer

Estrogen acts as a transcription factor, increasing cyclin production and promoting cell division.

Question 14

Which of the following statements about the mitotic spindle is correct?

Accepted Answer

It is composed of microtubules and is essential for chromosome movement.

Question 15

A cell is observed to have chromosomes aligned at the metaphase plate, but does not proceed to anaphase. What is the most likely explanation?

Accepted Answer

Not all kinetochores are properly attached to spindle fibers, so the metaphase checkpoint is not satisfied.

Question 16

Which of the following best explains why mitosis is considered a 'high fidelity' process?

Accepted Answer

It ensures that each daughter cell receives an exact copy of the parent cell's DNA.

Question 17

Which of the following events occurs during prometaphase of mitosis?

Accepted Answer

Chromosomes condense and the nuclear envelope breaks down.

Question 18

A patient is diagnosed with a tumor in which cells continue to divide even when crowded and in the absence of growth factors. Which cellular process is most likely defective?

Accepted Answer

Density-dependent inhibition and growth factor signaling

Question 19

Which of the following best describes the role of the G2 checkpoint in the cell cycle?

Accepted Answer

It verifies that DNA replication is complete and accurate before mitosis.

Question 20

If a mutation causes a cell to produce non-functional p53 protein, what is the most likely consequence?

Accepted Answer

The cell will fail to halt the cell cycle in response to DNA damage, increasing cancer risk.

Chapter 12: Mitosis and Regulation of the Eukaryotic Cell Cycle

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