Question 1

During which phase of meiosis does homologous recombination (crossing over) occur, and what is its primary evolutionary consequence?

Accepted Answer

During prophase I; it increases genetic diversity by creating new allele combinations.

Question 2

If a diploid cell (2n = 4) undergoes meiosis, how many chromosomes will each resulting gamete contain?

Accepted Answer

Each gamete will contain 2 chromosomes ($$n = 2).$$

Question 3

Which of the following best describes the Law of Independent Assortment?

Accepted Answer

Nonhomologous chromosome pairs align independently during Metaphase I, resulting in random combinations of alleles in gametes.

Question 4

What is the ploidy and DNA content of a cell immediately after Meiosis I, but before Meiosis II?

Accepted Answer

Haploid ($$n$$), but with 2x DNA content relative to a gamete.

Question 5

Which event is unique to meiosis and does NOT occur during mitosis?

Accepted Answer

Homologous chromosomes pair and undergo crossing over.

Question 6

A human zygote is formed by the fusion of two gametes. What is the chromosome number of the zygote?

Accepted Answer

46 chromosomes ($$2n = 46)$$

Question 7

Which mechanism contributes MOST to genetic variation in sexually reproducing populations?

Accepted Answer

Mutation

Question 8

In a Punnett square, what do the letters along the margins represent?

Accepted Answer

The alleles present in the gametes of each parent.

Question 9

Which of the following is TRUE regarding mitosis and meiosis?

Accepted Answer

Mitosis produces two identical diploid cells; meiosis produces four unique haploid cells.

Question 10

During which stage of meiosis do homologous chromosomes separate?

Accepted Answer

Anaphase I

Question 11

A cell with genotype AaBb undergoes meiosis. How many different gamete types can be produced, assuming independent assortment and no crossing over?

Accepted Answer

4 ($$AB$$, $$Ab$$, $$aB$$, $$ab)$$

Question 12

Which process restores the diploid chromosome number in sexually reproducing organisms?

Accepted Answer

Fertilization

Question 13

What is the main advantage of sexual reproduction compared to asexual reproduction?

Accepted Answer

It increases genetic variation in the population.

Question 14

Which of the following best describes the outcome of meiosis II?

Accepted Answer

Sister chromatids are separated, resulting in haploid cells with single chromosomes.

Question 15

If a mutation occurs during DNA replication in meiosis, what is the potential consequence for the offspring?

Accepted Answer

The mutation may be inherited by the offspring if it is present in the gamete.

Question 16

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

Accepted Answer

Cytokinesis

Question 17

What is the chromosome number and ploidy of a human somatic cell after mitosis?

Accepted Answer

46 chromosomes, diploid ($$2n)$$

Question 18

Which phase of meiosis is responsible for the Law of Segregation?

Accepted Answer

Anaphase I

Question 19

Why does meiosis maintain ploidy in a population?

Accepted Answer

It reduces chromosome number by half before fertilization, preventing doubling of chromosomes in each generation.

Question 20

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

Accepted Answer

Genetic variation is generated by crossing over, independent assortment, and random fertilization.

Inheritance and Sources of Genetic Variation: Meiosis, Mitosis, and Mendelian Laws

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