Question 1

During which phase of the cell cycle does DNA replication occur, and what is the significance of this process for cell division?

Accepted Answer

DNA replication occurs during the S phase, providing each daughter cell with an identical set of genetic material.

Question 2

Which of the following best describes the role of the mitotic spindle during mitosis?

Accepted Answer

It separates sister chromatids by attaching to kinetochores and pulling them toward opposite poles.

Question 3

A researcher observes a cell with chromosomes aligned at the metaphase plate. Which checkpoint must be passed for the cell to proceed to anaphase, and what is being checked?

Accepted Answer

M checkpoint; checks that all chromosomes are properly attached to spindle microtubules.

Question 4

Which of the following statements about cytokinesis in plant and animal cells is correct?

Accepted Answer

Animal cells form a cleavage furrow, while plant cells form a cell plate that develops into a new cell wall.

Question 5

If a human somatic cell (2n = 46) undergoes mitosis, how many chromosomes will each daughter cell have after cytokinesis?

Accepted Answer

$$46$$

Question 6

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

Accepted Answer

They escape normal cell cycle controls and continue dividing even when signals to stop are present.

Question 7

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

Accepted Answer

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

Question 8

A cell is observed to have condensed chromosomes, a disintegrating nuclear envelope, and spindle fibers attaching to kinetochores. Which stage of mitosis is this cell in?

Accepted Answer

Prometaphase

Question 9

Which of the following is a key difference between binary fission in prokaryotes and mitosis in eukaryotes?

Accepted Answer

Mitosis requires the breakdown of the nuclear envelope, while binary fission does not involve a nucleus.

Question 10

A mutation causes a cell to skip the G1 checkpoint and enter S phase without proper regulation. What is a likely consequence?

Accepted Answer

The cell may replicate damaged DNA, increasing the risk of cancer.

Question 11

Which of the following best describes the 'Pac-man' mechanism during anaphase?

Accepted Answer

Motor proteins on kinetochores 'walk' chromosomes along microtubules, which depolymerize at the kinetochore end.

Question 12

Which of the following is NOT a function of cell division in multicellular organisms?

Accepted Answer

Production of energy

Question 13

What would happen if the enzyme separase failed to function during mitosis?

Accepted Answer

Sister chromatids would not separate during anaphase.

Question 14

Which of the following best explains why mature nerve and muscle cells do not divide?

Accepted Answer

They remain permanently in the G0 phase and do not receive signals to re-enter the cell cycle.

Question 15

A scientist treats dividing cells with Taxol, a drug that prevents microtubule depolymerization. What is the most likely effect on mitosis?

Accepted Answer

Cells will arrest at metaphase because sister chromatids cannot be separated.

Question 16

Which of the following equations correctly represents the chromosome number in human gametes compared to somatic cells?

Accepted Answer

$$n = 23 in $$gametes, $$2n = 46 in $$somatic cells

Question 17

Which of the following is a real-world example of density-dependent inhibition in cell division?

Accepted Answer

A wound healing process where cells stop dividing once the wound is closed.

Question 18

What is the primary function of the G2 phase in the cell cycle?

Accepted Answer

Cell growth and completion of protein and centriole replication in preparation for mitosis

Question 19

Which of the following best describes the relationship between cyclin concentration and Cdk activity during the cell cycle?

Accepted Answer

Cdk activity rises and falls with changes in cyclin concentration.

The Cell Cycle and Mitosis: Structure, Function, and Regulation

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