Question 1

Which of the following best explains why meiosis, and not mitosis, is necessary for sexual reproduction in humans?

Accepted Answer

Meiosis reduces the chromosome number by half, preventing chromosome doubling in each generation.

Question 2

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

Accepted Answer

Crossing over occurs during prophase I and increases genetic variation among gametes.

Question 3

If a diploid cell with $$2n = 8$$ undergoes meiosis, how many chromosomes will each resulting gamete contain?

Accepted Answer

$$4$$

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

A geneticist is studying a species with a haploid number $$n = 5. $$According to the formula $$2^n$$, how many possible chromosome combinations can result from independent assortment during meiosis?

Accepted Answer

$$32$$

Question 6

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

Accepted Answer

Four haploid cells, each genetically distinct from each other and the parent cell.

Question 7

Which process is responsible for the formation of recombinant chromosomes during meiosis?

Accepted Answer

Crossing over

Question 8

A mutation prevents the formation of chiasmata during meiosis. Which of the following is most likely to be affected?

Accepted Answer

The genetic variation among gametes due to reduced crossing over

Question 9

Which of the following statements about the differences between mitosis and meiosis is correct?

Accepted Answer

Synapsis and crossing over occur in meiosis but not in mitosis.

Question 10

In humans, how many genetically unique gametes can be produced by independent assortment alone, given $$n = 23$$?

Accepted Answer

$$2^{23}$$, or about 8 million

Question 11

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 12

A cell in prophase I of meiosis contains 12 chromosomes. After telophase II and cytokinesis, how many chromosomes will each daughter cell have?

Accepted Answer

$$6$$

Question 13

Which of the following is a direct result of the process of synapsis during meiosis?

Accepted Answer

Formation of tetrads

Question 14

Why does meiosis II not include another round of chromosome replication?

Accepted Answer

Because DNA replication only occurs once prior to meiosis I

Question 15

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

Accepted Answer

Replication of DNA during interphase

Question 16

A scientist observes a cell with tetrads aligned at the metaphase plate. Which stage is this cell in?

Accepted Answer

Metaphase I of meiosis

Question 17

Which of the following best describes the role of meiosis in the life cycle of multicellular organisms?

Accepted Answer

It produces gametes and introduces genetic variability.

Question 18

If a mutation caused the failure of cytokinesis after meiosis II, what would be the result?

Accepted Answer

One cell with four haploid nuclei

Question 19

Which of the following is true regarding the genetic content of the four daughter cells produced by meiosis?

Accepted Answer

They are genetically distinct from each other and from the parent cell.

Question 20

A patient is diagnosed with a genetic disorder caused by nondisjunction during meiosis. Which of the following best describes what happened during gamete formation?

Accepted Answer

Homologous chromosomes or sister chromatids failed to separate properly.

Meiosis: The Cellular Basis of Sexual Reproduction and Genetic Variation

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