Question 1

Which of the following best describes the role of the centromere during mitosis?

Accepted Answer

It is the site where spindle fibers attach to chromosomes, ensuring proper segregation of sister chromatids.

Question 2

During which phase of the cell cycle does DNA replication occur, resulting in duplicated chromosomes each consisting of two sister chromatids?

Accepted Answer

S phase

Question 3

A researcher observes a cell with chromosomes aligned at the center of the cell, attached to spindle fibers from opposite poles. Which stage of mitosis is this cell in?

Accepted Answer

Metaphase

Question 4

Which of the following equations correctly represents the number of chromosomes and chromatids in a human somatic cell during metaphase of mitosis?

Accepted Answer

$$46$$ chromosomes, $$92$$ chromatids

Question 5

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

Accepted Answer

They phosphorylate target proteins to trigger progression through cell cycle checkpoints.

Question 6

A mutation in the gene encoding CAK (Cdk-activating kinase) results in a non-functional protein. What is the most likely consequence for the cell cycle?

Accepted Answer

MPF will not become fully active, preventing the cell from entering mitosis.

Question 7

Which of the following best explains why cancer cells can divide indefinitely in culture?

Accepted Answer

They do not exhibit density-dependent inhibition or anchorage dependence.

Question 8

During anaphase, which of the following events occurs?

Accepted Answer

Sister chromatids are pulled apart toward opposite poles of the cell.

Question 9

Which of the following statements about the role of microtubules in mitosis is correct?

Accepted Answer

Microtubules attach to kinetochores and help segregate chromosomes during anaphase.

Question 10

A cell is observed to have a high concentration of cyclin, but cell division does not occur. Which of the following is the most likely explanation?

Accepted Answer

The corresponding Cdk is inactive or absent, preventing progression through the checkpoint.

Question 11

Which of the following best describes the function of growth factors in the cell cycle?

Accepted Answer

They are proteins that stimulate other cells to divide by binding to specific receptors.

Question 12

If a cell fails to attach to a substrate, which of the following is most likely to occur?

Accepted Answer

The cell will not divide due to lack of anchorage dependence.

Question 13

Which of the following is a direct result of the activity of MPF (Maturation Promoting Factor) in the cell cycle?

Accepted Answer

Initiation of mitosis by phosphorylating target proteins.

Question 14

A scientist observes that a certain cell line continues to divide even when crowded and not attached to a substrate. What is the most likely explanation?

Accepted Answer

The cells have lost both density-dependent inhibition and anchorage dependence, typical of cancer cells.

Question 15

Which of the following best explains the 'high fidelity' of genetic information transmission during mitosis?

Accepted Answer

Each daughter cell receives an identical set of chromosomes as the parent cell.

Question 16

Which of the following is a function of the spindle apparatus during mitosis?

Accepted Answer

It separates sister chromatids by pulling them toward opposite poles.

Question 17

A cell is observed to have completed DNA replication but has not yet begun mitosis. Which phase of the cell cycle is it most likely in?

Accepted Answer

G2 phase

Question 18

Which of the following statements about the relationship between the cell cycle and cancer is correct?

Accepted Answer

Cancer cells often have mutations that disrupt normal cell cycle control, allowing uncontrolled division.

Question 19

Which of the following best describes the role of kinases in the cell cycle?

Accepted Answer

They phosphorylate other proteins to regulate cell cycle progression.

Question 20

A cell is exposed to a drug that prevents the degradation of cyclin. What is the most likely effect on the cell cycle?

Accepted Answer

The cell may fail to exit mitosis, leading to abnormal cell cycle progression.

Chapter 12: Mitosis and the Regulation of the Cell Cycle

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