Question 1

Which of the following best explains why siblings from the same parents are not genetically identical, despite sharing the same parents?

Accepted Answer

Because independent assortment and crossing over during meiosis create new combinations of alleles.

Question 2

During which phase of meiosis does crossing over occur, and what is its significance?

Accepted Answer

Prophase I; it increases genetic diversity by exchanging DNA between homologous chromosomes.

Question 3

A human somatic cell contains 46 chromosomes. After meiosis, how many chromosomes will each gamete contain?

Accepted Answer

$$23$$

Question 4

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

Accepted Answer

Homologous chromosome pairs (tetrads) align at the metaphase plate.

Question 5

What is the primary function of tumor suppressor genes such as p53 in the cell cycle?

Accepted Answer

To repair DNA damage or trigger apoptosis if damage is irreparable.

Question 6

If a mutation disables a tumor suppressor gene, what is the most likely consequence for the cell?

Accepted Answer

The cell may divide uncontrollably, increasing cancer risk.

Question 7

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 8

What is the role of cyclins and cyclin-dependent kinases (CDKs) in the cell cycle?

Accepted Answer

They regulate progression through the cell cycle by activating or deactivating target proteins.

Question 9

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

Accepted Answer

Homologous chromosomes are similar but not identical, one from each parent; sister chromatids are identical copies formed by DNA replication.

Question 10

Which process is responsible for the restoration of the diploid chromosome number after meiosis?

Accepted Answer

Fertilization

Question 11

A cell with genotype $$2n = 8$$ undergoes meiosis. How many chromosomes will each resulting gamete have?

Accepted Answer

$$4$$

Question 12

Which of the following mechanisms does NOT contribute to genetic variation in sexually reproducing organisms?

Accepted Answer

Replication of DNA during S phase

Question 13

Which of the following statements about meiosis II is correct?

Accepted Answer

It separates sister chromatids, similar to mitosis.

Question 14

If nondisjunction occurs during anaphase I of meiosis, what is the result?

Accepted Answer

Some gametes will have an extra chromosome, and some will be missing one.

Question 15

Which of the following best describes the outcome of meiosis in animals?

Accepted Answer

Four genetically unique haploid gametes

Question 16

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

Accepted Answer

Meiosis involves two rounds of division and produces haploid cells; mitosis involves one round and produces diploid cells.

Question 17

A scientist observes a cell in which homologous chromosomes are paired and exchanging genetic material. Which stage is this cell most likely in?

Accepted Answer

Prophase I

Question 18

Which of the following equations correctly represents the reduction in chromosome number during meiosis?

Accepted Answer

$$2n \rightarrow n$$

Question 19

Which of the following best explains why asexual reproduction does not contribute to genetic diversity in a population?

Accepted Answer

It produces offspring that are genetically identical to the parent.

Question 20

Which of the following is NOT a function of meiosis?

Accepted Answer

Repairing damaged tissues

Meiosis: Mechanisms and Significance in Sexual Reproduction

Study Guide - Practice Questions