CLEP Biology Cell Division: Mitosis and Meiosis Flashcards

How many rounds of nuclear division occur during meiosis?

Answer: Two

Meiosis involves two sequential rounds of division—meiosis I (reductional) and meiosis II (equational)—to produce four haploid cells from one diploid cell.

Crossing over (recombination) between non-sister chromatids of homologous chromosomes occurs primarily during which stage?

Answer: Prophase I

During prophase I, homologous chromosomes synapse and crossing over occurs at chiasmata, creating recombinant chromosomes with new allele combinations.

A human diploid cell (2n = 46) undergoes meiosis. How many chromosomes are present in each resulting gamete?

Answer: 23

Meiosis reduces the chromosome number by half; each gamete receives one chromosome from each homologous pair, yielding 23 chromosomes (n = 23).

Homologous chromosomes pair up to form bivalents (tetrads) during which phase of meiosis?

Answer: Prophase I

During prophase I, homologous chromosomes undergo synapsis facilitated by the synaptonemal complex, forming bivalents (each consisting of four chromatids).

The separation of homologous chromosome pairs to opposite poles of the cell is the defining event of:

Answer: Anaphase of meiosis I

Anaphase I is the reductional step where homologs (not sister chromatids) are pulled apart, reducing the chromosome number in each half of the cell.

Which of the following correctly describes the final products of a complete meiotic division?

Answer: 4 haploid cells

Meiosis produces four genetically distinct haploid cells; in males these become sperm, while in females one becomes an egg and the other three are polar bodies.

Genetic recombination (crossing over) between non-sister chromatids primarily occurs during which substage of prophase I?

Answer: Pachytene

During pachytene, homologous chromosomes are fully synapsed and chiasmata form as the physical sites where DNA strands are exchanged between non-sister chromatids.