Question 1

During which phase of the cell cycle does DNA replication occur, resulting in duplicated chromosomes composed of sister chromatids?

Accepted Answer

S phase

Question 2

Which of the following best describes the difference between chromosomes in interphase and chromosomes in mitosis/meiosis?

Accepted Answer

Interphase chromosomes are diffuse and actively transcribed, while mitotic chromosomes are tightly coiled and transcriptionally inactive.

Question 3

If a human somatic cell undergoes mitosis, how many chromosomes and chromatids will be present in each daughter cell at the end of the process?

Accepted Answer

46 chromosomes and 46 chromatids

Question 4

Which equation correctly represents the change in chromosome number during meiosis in humans?

Accepted Answer

$$46 \rightarrow 23$$

Question 5

What is the primary genetic consequence of crossing-over during meiosis?

Accepted Answer

It produces recombinant chromosomes, increasing genetic variation among gametes.

Question 6

A cell in metaphase of mitosis contains 46 chromosomes and 92 chromatids. What will be the number of chromosomes and chromatids in each daughter cell after telophase?

Accepted Answer

46 chromosomes and 46 chromatids

Question 7

Which process is responsible for the random distribution of maternal and paternal chromosomes into gametes during meiosis?

Accepted Answer

Independent assortment

Question 8

Why does gene transcription decrease during chromosome condensation in mitosis and meiosis?

Accepted Answer

Because tightly coiled chromosomes prevent access to transcription machinery.

Question 9

Which of the following is a correct statement about the centromere during the cell cycle?

Accepted Answer

The centromere holds sister chromatids together after DNA replication in S phase.

Question 10

A mutation occurs in a gene that disrupts the formation of the synaptonemal complex during meiosis. What is the most likely consequence?

Accepted Answer

Impaired pairing and recombination of homologous chromosomes, reducing genetic diversity in gametes.

Question 11

Which stage of mitosis is characterized by the alignment of chromosomes at the cell's equatorial plane?

Accepted Answer

Metaphase

Question 12

If a human cell starts with 46 chromosomes and undergoes meiosis, how many possible combinations of chromosomes can result from independent assortment alone?

Accepted Answer

$$2^{23}$$

Question 13

Which of the following best explains why older fathers are linked to increased new mutations in offspring?

Accepted Answer

Sperm cells in older men undergo more mitotic divisions, increasing the chance of replication errors.

Question 14

Which of the following is NOT a consequence of meiotic nondisjunction?

Accepted Answer

Production of genetically identical gametes

Question 15

During which stage of mitosis do sister chromatids separate and move toward opposite poles?

Accepted Answer

Anaphase

Question 16

Which of the following statements about oogenesis in humans is correct?

Accepted Answer

Oogenesis results in one functional egg and polar bodies from each precursor cell.

Question 17

Which of the following is a key difference between spermatogenesis and oogenesis in humans?

Accepted Answer

Spermatogenesis is continuous throughout life, while oogenesis is largely completed before birth.

Question 18

Which of the following best describes the configuration of chromosomes during metaphase of mitosis?

Accepted Answer

Chromosomes are tightly coiled, aligned at the metaphase plate, and each consists of two sister chromatids.

Question 19

Which of the following events occurs during prophase I of meiosis but NOT during mitosis?

Accepted Answer

Pairing of homologous chromosomes and crossing-over

Cell Cycle, Chromosome Structure, and Cell Division in Human Genetics

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