Question 1

Which of the following best explains why daughter cells produced by mitosis are genetically identical to the parent cell?

Accepted Answer

Because DNA replication occurs before cell division, ensuring each daughter cell receives an exact copy of the genome.

Question 2

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

Accepted Answer

S phase

Question 3

A scientist observes a cell with condensed chromosomes aligned at the center of the cell. Which stage of mitosis is this cell in?

Accepted Answer

Metaphase

Question 4

Which of the following best describes the role of cyclin-dependent kinases (Cdks) in the cell cycle?

Accepted Answer

They regulate the progression of the cell cycle by phosphorylating target proteins only when bound to cyclins.

Question 5

A mutation causes a cell to skip the G1 checkpoint. Which of the following is a likely consequence?

Accepted Answer

The cell may replicate damaged or incomplete DNA, leading to genetic instability.

Question 6

Which of the following events distinguishes cytokinesis in plant cells from that in animal cells?

Accepted Answer

Plant cells form a cell plate, while animal cells form a cleavage furrow.

Question 7

If a cell has 12 chromosomes at the start of G1, how many chromosomes will each daughter cell have after mitosis and cytokinesis?

Accepted Answer

12

Question 8

Which checkpoint in the cell cycle ensures that all chromosomes are properly attached to the spindle before anaphase begins?

Accepted Answer

M checkpoint (spindle checkpoint)

Question 9

A researcher treats cells with a drug that prevents microtubule formation. Which stage of mitosis will be directly affected?

Accepted Answer

Metaphase, because chromosomes cannot align without spindle fibers.

Question 10

Which of the following best describes homologous chromosomes?

Accepted Answer

They are pairs of chromosomes, one from each parent, that have the same genes at the same loci but may have different alleles.

Question 11

A cell is observed to have twice the normal amount of DNA but has not yet begun mitosis. Which phase is it most likely in?

Accepted Answer

G2 phase

Question 12

Which of the following external factors can influence the cell cycle control system in multicellular organisms?

Accepted Answer

Growth factors released by neighboring cells

Question 13

A patient is diagnosed with a tumor caused by uncontrolled cell division. Which malfunction in the cell cycle is most likely responsible?

Accepted Answer

Failure of cell cycle checkpoints to detect DNA damage

Question 14

Which of the following equations correctly represents the relationship between chromosome number before and after DNA replication in mitosis?

Accepted Answer

If $n$ is the number of chromosomes, after DNA replication there are $n$ chromosomes, each consisting of two sister chromatids.

Question 15

Which of the following best describes the difference between chromatin and chromosomes?

Accepted Answer

Chromatin is the less condensed form of DNA present during interphase, while chromosomes are the highly condensed form visible during mitosis.

Question 16

A cell is exposed to a chemical that inhibits the activity of MPF (Maturation Promoting Factor). What is the most likely effect on the cell cycle?

Accepted Answer

The cell will be unable to enter mitosis from G2 phase.

Question 17

Which of the following is a key difference between mitosis in animal cells and plant cells?

Accepted Answer

Animal cells use a contractile ring to form a cleavage furrow, while plant cells build a new cell wall from vesicles at the center.

Question 18

If a cell fails to separate its sister chromatids during mitosis, what is the most likely outcome for the daughter cells?

Accepted Answer

One daughter cell will have extra chromosomes, and the other will have fewer chromosomes.

Question 19

Which of the following best describes the function of checkpoints in the cell cycle?

Accepted Answer

They ensure that critical events such as DNA replication and chromosome alignment are completed correctly before the cell proceeds to the next phase.

Study Notes: The Cell Cycle

Study Guide - Practice Questions