Question 1

Which of the following best describes the difference between a gene and an allele?

Accepted Answer

A gene is a segment of DNA encoding a protein, while an allele is an alternative version of that gene.

Question 2

A human cell with 23 chromosomes is:

Accepted Answer

A haploid gamete cell.

Question 3

If a species has a diploid number of 2n = 16, how many chromosomes are present in each haploid gamete?

Accepted Answer

$$8$$

Question 4

Which of the following statements about homologous chromosomes is correct?

Accepted Answer

They carry the same genes but may have different alleles.

Question 5

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 6

What is the result of independent assortment during meiosis, and how is the number of possible combinations calculated?

Accepted Answer

It produces genetic diversity; the number of combinations is $$2^n$$, where $$n is $$the haploid number.

Question 7

A cell undergoes meiosis and produces four gametes. If nondisjunction occurs during anaphase II, what is a possible outcome?

Accepted Answer

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

Question 8

Which of the following processes occurs in meiosis but not in mitosis?

Accepted Answer

Synapsis of homologous chromosomes during prophase I.

Question 9

What is the main difference between Meiosis I and Meiosis II?

Accepted Answer

Meiosis I separates homologous chromosomes, while Meiosis II separates sister chromatids.

Question 10

Which of the following best explains why siblings from the same parents can look very different from each other?

Accepted Answer

Genetic variation is introduced during meiosis by crossing over and independent assortment.

Question 11

During which stage of meiosis do homologous chromosomes align in pairs at the metaphase plate?

Accepted Answer

Metaphase I

Question 12

Aneuploid cells are produced as a result of which meiotic error?

Accepted Answer

Nondisjunction, where chromosomes fail to separate properly during anaphase.

Question 13

Which of the following statements is true regarding the life cycle of sexually reproducing organisms?

Accepted Answer

It includes mitosis, meiosis, gamete formation, and fertilization.

Question 14

If an organism has a haploid number of $$n = 4$$, how many genetically unique gametes can it produce due to independent assortment?

Accepted Answer

$$2^4 = 16$

Question 15

Which of the following best describes the outcome of fertilization in humans?

Accepted Answer

A haploid sperm and a haploid egg fuse to form a diploid zygote.

Question 16

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

Accepted Answer

Mitosis produces genetically identical cells, while meiosis produces genetically diverse gametes.

Question 17

During which stage of meiosis do sister chromatids separate?

Accepted Answer

Anaphase II

Question 18

Which of the following is NOT a source of genetic variation in sexually reproducing organisms?

Accepted Answer

Mitosis

Question 19

A cell with two sets of chromosomes is described as:

Accepted Answer

Diploid

Question 20

Which of the following best explains why meiosis is essential for sexual reproduction?

Accepted Answer

It reduces the chromosome number by half, ensuring that fertilization restores the diploid state.

Meiosis: The Basis of Sexual Reproduction – Study Notes

Study Guide - Practice Questions