Question 1

Which of the following best describes the difference between homologous chromosomes and sister chromatids?

Accepted Answer

Homologous chromosomes are a pair, one from each parent, with genes for the same traits at the same loci, while sister chromatids are identical copies formed during DNA replication.

Question 2

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

Accepted Answer

DNA replication occurs during the S phase, resulting in chromosomes composed of two sister chromatids.

Question 3

A muscle cell in a human undergoes mitosis. How many chromosomes will each daughter cell contain after cytokinesis is complete?

Accepted Answer

Each daughter cell will contain 46 chromosomes.

Question 4

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

Accepted Answer

Homologous chromosomes pair up to form tetrads.

Question 5

A geneticist is studying a cell that has just completed meiosis I. Which of the following statements about the resulting cells is correct?

Accepted Answer

Each cell is haploid and contains 23 chromosomes, each with two sister chromatids.

Question 6

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

Accepted Answer

Meiosis reduces the chromosome number by half, so that fertilization restores the diploid number in the zygote.

Question 7

During anaphase of mitosis, what is the fate of the sister chromatids, and how does this differ from anaphase I of meiosis?

Accepted Answer

In mitosis, sister chromatids separate and move to opposite poles; in meiosis I, homologous chromosomes separate but sister chromatids remain together.

Question 8

A cell is observed with 23 chromosomes lined up at the equator, each consisting of two sister chromatids. Which phase and division is this cell most likely in?

Accepted Answer

Metaphase II of meiosis

Question 9

If a mutation prevented the formation of kinetochores during cell division, which process would be directly affected?

Accepted Answer

The attachment of spindle microtubules to chromosomes, preventing proper segregation during mitosis and meiosis.

Question 10

A patient has a genetic disorder resulting from nondisjunction during meiosis II. Which of the following best describes what occurred?

Accepted Answer

Sister chromatids failed to separate during meiosis II, leading to gametes with abnormal chromosome numbers.

Question 11

Which of the following equations correctly represents the chromosome number in human cells after meiosis II?

Accepted Answer

$$n = 23$$

Question 12

A nerve cell is said to be in the G0 phase. What does this indicate about the cell's activity?

Accepted Answer

The cell is not preparing to divide and has exited the cell cycle.

Question 13

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

Accepted Answer

The cytoplasm divides, resulting in two separate daughter cells.

Question 14

A cell with 46 chromosomes undergoes meiosis. How many genetically unique gametes are produced, and how many chromosomes does each contain?

Accepted Answer

Four gametes, each with 23 chromosomes.

Question 15

Which of the following is a direct result of the pairing of homologous chromosomes during prophase I of meiosis?

Accepted Answer

Formation of tetrads, which allows for genetic recombination (crossing over).

Question 16

If a human zygote is formed, what is the chromosome number, and how is this number achieved?

Accepted Answer

46 chromosomes, achieved by the fusion of two haploid gametes (each with 23 chromosomes).

Question 17

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

Accepted Answer

Because DNA is replicated exactly during the S phase and distributed equally during mitosis.

Question 18

Which of the following statements about autosomal chromosomes is correct?

Accepted Answer

They are chromosomes 1-22 and contain genes for somatic characteristics.

Question 19

A cell is observed in metaphase I of meiosis. What is the arrangement of chromosomes at this stage?

Accepted Answer

23 tetrads (pairs of homologous chromosomes) line up at the equator.

Question 20

Which of the following best describes the role of the centrosome during cell division?

Accepted Answer

It organizes the spindle microtubules that separate chromosomes.

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

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