Question 1

A somatic cell of a species has a diploid number ($$2n) of 8. $$How many chromosomes will be present in each gamete produced by this species after meiosis?

Accepted Answer

4

Question 2

Which of the following best describes the main purpose of meiosis in sexually reproducing organisms?

Accepted Answer

To reduce the chromosome number by half and generate genetic diversity in gametes

Question 3

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

Accepted Answer

Prophase I; it increases genetic variation by exchanging genetic material between homologous chromosomes

Question 4

If a cell with a diploid number of $$2n = 6$$ undergoes meiosis, how many genetically unique gametes can be produced by independent assortment alone (ignoring crossing over)? Use the formula $$2^n$$, where $$n is $$the haploid number.

Accepted Answer

$$2^3 = 8$

Question 5

Which of the following statements about the ploidy of cells is correct?

Accepted Answer

Somatic cells are diploid, and gametes are haploid

Question 6

A mutation prevents crossing over during meiosis in a certain organism. Which of the following would most likely be affected?

Accepted Answer

The genetic diversity among gametes

Question 7

Which of the following is NOT a source of genetic variation in sexual reproduction?

Accepted Answer

Replication of DNA during S phase

Question 8

During which stage of meiosis do homologous chromosomes separate?

Accepted Answer

Anaphase I

Question 9

A human zygote is formed by the fusion of two gametes. What is the ploidy of the zygote, and how does this relate to the chromosome number in somatic cells?

Accepted Answer

Diploid; it has the same number of chromosomes as somatic cells

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 arises from independent assortment, crossing over, and random fertilization

Question 11

In a species with a diploid number of $$2n = 10$$, how many chromosomes will be present in each cell at the end of meiosis II?

Accepted Answer

5

Question 12

Which of the following events occurs in both mitosis and meiosis?

Accepted Answer

Separation of sister chromatids

Question 13

A cell undergoes meiosis but fails to separate homologous chromosomes during Anaphase I. What is the likely result?

Accepted Answer

Some gametes will have an abnormal number of chromosomes (nondisjunction)

Question 14

Which of the following statements correctly compares mitosis and meiosis?

Accepted Answer

Mitosis produces diploid cells, while meiosis produces haploid cells

Question 15

If an organism has a haploid number ($$n) of 7$$, how many different chromosome combinations can be produced in its gametes by independent assortment alone?

Accepted Answer

$$2^7 = 128$

Question 16

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

Accepted Answer

Sister chromatids are separated, resulting in haploid cells

Question 17

A geneticist observes that two genes are located far apart on the same chromosome. Which process during meiosis is most likely to separate these genes into different gametes?

Accepted Answer

Crossing over during Prophase I

Question 18

Which of the following is true regarding the chromosome content of cells at the end of meiosis I?

Accepted Answer

Cells are haploid, but chromosomes are still composed of two sister chromatids

Question 19

Which of the following scenarios would most likely result in a zygote with an abnormal chromosome number?

Accepted Answer

Nondisjunction during Anaphase I or II of meiosis

Cell Division: Meiosis Part 2 – Mechanisms and Genetic Variation

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