Question 1

Which of the following best describes the main outcome of mitosis in eukaryotic cells?

Accepted Answer

Two genetically identical diploid daughter cells are produced.

Question 2

During which phase of meiosis does crossing over (homologous recombination) primarily occur, and what is its biological significance?

Accepted Answer

Prophase I; it increases genetic diversity in gametes.

Question 3

If a human diploid cell (2n) contains 23 pairs of homologous chromosomes, how many different gametes could theoretically be produced by independent assortment alone (ignoring crossing over)?

Accepted Answer

$$2^{23}$$

Question 4

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

Accepted Answer

Spindle Assembly Checkpoint (SAC)

Question 5

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

Accepted Answer

They catalyze the addition of phosphate groups to target proteins, regulating cell cycle progression.

Question 6

A mutation causes a cell to bypass the G1 checkpoint even when DNA is damaged. What is a likely consequence of this mutation?

Accepted Answer

The cell may accumulate mutations, increasing the risk of cancer.

Question 7

Which of the following events distinguishes meiosis I from mitosis?

Accepted Answer

Pairing and separation of homologous chromosomes

Question 8

What is the result of non-disjunction during meiosis?

Accepted Answer

Aneuploidy, where gametes have an abnormal number of chromosomes

Question 9

Which of the following best explains why sexual reproduction leads to greater genetic variation than asexual reproduction?

Accepted Answer

Sexual reproduction includes crossing over and independent assortment during meiosis.

Question 10

A cell is exposed to radiation, resulting in DNA damage. Which protein is most likely to accumulate and halt the cell cycle to allow for DNA repair?

Accepted Answer

p53

Question 11

During which stage of meiosis do homologous chromosomes align at the equator of the cell?

Accepted Answer

Metaphase I

Question 12

Which of the following is a direct biological consequence of a failure in the spindle assembly checkpoint (SAC)?

Accepted Answer

Chromosomes may not segregate properly, leading to aneuploidy.

Question 13

If two gametes, each with $$2^{23}$$ possible combinations due to independent assortment, fuse during fertilization, how many different zygotes could theoretically be produced (ignoring crossing over)?

Accepted Answer

$$2^{46}$$

Question 14

Which of the following statements about cyclins is correct?

Accepted Answer

Cyclins are synthesized and degraded at specific stages to regulate CDK activity.

Question 15

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

Accepted Answer

Production of gametes

Question 16

A researcher observes that a cell has completed DNA replication but does not enter mitosis. Which checkpoint is most likely preventing progression?

Accepted Answer

G2/M checkpoint

Question 17

Which of the following best describes the role of the synaptonemal complex during meiosis?

Accepted Answer

It facilitates the pairing of homologous chromosomes and crossing over in prophase I.

Question 18

Which of the following scenarios would most likely result in uncontrolled cell division?

Accepted Answer

A mutation that inactivates p53, preventing cell cycle arrest after DNA damage.

Question 19

Which of the following is a key difference between mitosis and meiosis II?

Accepted Answer

Sister chromatids are separated in both, but meiosis II follows a reductional division.

Question 20

Which of the following best explains why errors in cell cycle checkpoints can lead to cancer?

Accepted Answer

Checkpoints prevent the division of cells with DNA damage or incomplete replication, so their failure allows propagation of mutations.

Cell Division: Mitosis, Meiosis, and Regulation in Eukaryotes

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