CLEP CLEP Biology Cell Division: Mitosis and Meiosis 3

Question 1

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

Accepted Answer

Synapsis of homologous chromosomes

Answer

Synapsis—the precise pairing of homologous chromosomes—is unique to meiosis I and is essential for crossing over and proper segregation of homologs.

Question 2

Independent assortment of chromosomes, which generates genetic diversity, occurs during:

Accepted Answer

Metaphase I of meiosis

Answer

During metaphase I, homologous pairs align at the metaphase plate independently of one another, so each pole randomly receives a mix of maternal and paternal chromosomes.

Question 3

At the end of meiosis I, what is the ploidy of the two resulting cells in a human?

Accepted Answer

Haploid (n = 23)

Answer

Meiosis I is the reductional division: each cell receives one member of each homologous pair, making each cell haploid with 23 chromosomes (each still consisting of two sister chromatids).

Question 4

Non-disjunction occurring during meiosis I results in gametes that are:

Accepted Answer

Either n+1 or n-1 for the affected chromosome

Answer

When homologs fail to separate in meiosis I, one secondary oocyte/spermatocyte gets both homologs and the other gets none, producing gametes with n+1 and n-1 after meiosis II.

Question 5

Which of the following events contributes to genetic variation by creating new combinations of alleles on the same chromosome?

Accepted Answer

Crossing over during prophase I

Answer

Crossing over physically exchanges segments between non-sister chromatids of homologous chromosomes, creating recombinant chromosomes with novel allele arrangements.

CLEP Practice Test

CLEP Practice Test

CLEP CLEP Biology Cell Division: Mitosis and Meiosis 3