Question 1

Which of the following best describes the difference between somatic cells and gametes in terms of chromosome number?

Accepted Answer

Somatic cells are diploid (2n) with 46 chromosomes, while gametes are haploid (n) with 23 chromosomes.

Question 2

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

Accepted Answer

DNA replication occurs during the S phase, resulting in 92 chromatids.

Question 3

A cell with 46 chromosomes undergoes mitosis. How many chromosomes will each daughter cell have after cytokinesis?

Accepted Answer

Each daughter cell will have 46 chromosomes.

Question 4

Which of the following events is unique to meiosis I and does NOT occur in mitosis?

Accepted Answer

Formation of tetrads (synapsis) and crossing over between homologous chromosomes.

Question 5

If a mutation occurs in a gene located on an autosomal chromosome, which of the following is true regarding its inheritance?

Accepted Answer

It can be inherited by both male and female offspring.

Question 6

During anaphase of mitosis, what is the primary event that occurs?

Accepted Answer

Sister chromatids separate and move to opposite poles.

Question 7

A patient’s karyotype shows 47 chromosomes. Which phase of the cell cycle would be best to observe this abnormality and why?

Accepted Answer

Metaphase, because chromosomes are condensed and aligned at the equator.

Question 8

Which of the following equations correctly represents the chromosome number in a human zygote after fertilization?

Accepted Answer

$n + n = 2n$

Question 9

Which checkpoint in the cell cycle ensures that DNA has been properly replicated before mitosis begins?

Accepted Answer

G2 checkpoint

Question 10

A cell is observed to have chromosomes lined up at the equator, each consisting of two sister chromatids. Which phase is this cell in?

Accepted Answer

Metaphase

Question 11

Which of the following best explains why meiosis is necessary for sexual reproduction in humans?

Accepted Answer

It reduces the chromosome number by half, preventing chromosome doubling in each generation.

Question 12

During which stage of meiosis do homologous chromosomes separate, and what is the result for chromosome number in the daughter cells?

Accepted Answer

Anaphase I; daughter cells become haploid.

Question 13

A mutation causes a cell to skip the S phase of the cell cycle. What would be the most likely consequence during mitosis?

Accepted Answer

The cell would not replicate its DNA, resulting in daughter cells with incomplete genetic material.

Question 14

Which of the following statements about homologous chromosomes is correct?

Accepted Answer

They carry genes for the same traits at the same loci but may have different alleles.

Question 15

In a clinical scenario, a patient is found to have a genetic disorder due to nondisjunction during meiosis II. Which of the following best describes the chromosomal content of the affected gamete?

Accepted Answer

It contains two copies of the same sister chromatid.

Question 16

Which of the following best describes the process and outcome of cytokinesis in animal cells?

Accepted Answer

Cytokinesis divides the cytoplasm, resulting in two separate daughter cells.

Question 17

Which of the following is true regarding the sex chromosomes in human somatic cells?

Accepted Answer

Females have two X chromosomes (XX), and males have one X and one Y chromosome (XY).

Question 18

A researcher observes a cell in which the nuclear envelope is breaking down, chromosomes are condensing, and spindle fibers are forming. Which phase is this?

Accepted Answer

Prophase

Question 19

Which of the following best explains the genetic diversity produced by meiosis?

Accepted Answer

Crossing over during prophase I and independent assortment during metaphase I.

Question 20

A cell is observed to have completed telophase II of meiosis. How many chromosomes and chromatids are present in each resulting cell?

Accepted Answer

23 chromosomes and 23 chromatids

Cell Cycle, Mitosis, and Meiosis: Structure and Function in Human Cells

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