If a parent cell has 48 chromosomes, how many does each daughter cell have at the end of meiosis II? 2) Which processes increase variation during meiosis? (This question will require more than a 1- or 2-word answer.) 3) What term describes the pairing of chromosomes during prophase I.
The Correct Answer and Explanation is:
Correct Answers:
- Each daughter cell has 24 chromosomes at the end of meiosis II.
- The processes that increase variation during meiosis are crossing over and independent assortment.
- The term that describes the pairing of chromosomes during prophase I is synapsis.
Explanation
During meiosis, a parent cell undergoes two consecutive divisions called meiosis I and meiosis II to produce four genetically unique daughter cells. If the parent cell has 48 chromosomes, it is diploid, meaning it contains two sets of chromosomes. Before meiosis begins, the chromosomes replicate during interphase, but the chromosome number remains the same at 48, now consisting of sister chromatids.
In meiosis I, homologous chromosomes separate. These are pairs of chromosomes, one from each parent, that carry similar genetic information. At the end of meiosis I, two cells are formed, each with 24 chromosomes. These chromosomes are still duplicated, consisting of sister chromatids. Meiosis I is therefore a reduction division because it halves the chromosome number.
Meiosis II resembles a typical mitotic division. The sister chromatids of each chromosome are separated and distributed into two new cells. As a result, four daughter cells are formed, each with 24 chromosomes, which is half the original diploid number. These cells are haploid and can become gametes (sperm or egg cells in animals).
Genetic variation during meiosis arises through crossing over and independent assortment. Crossing over occurs during prophase I, when homologous chromosomes come together and exchange segments of genetic material. This reshuffles alleles between maternal and paternal chromosomes. Independent assortment occurs during metaphase I, when homologous pairs line up randomly along the metaphase plate. Each pair’s orientation is independent of the others, leading to many possible combinations of chromosomes in gametes.
The pairing of homologous chromosomes during prophase I is called synapsis. This close association allows crossing over to occur at points called chiasmata. Synapsis ensures accurate chromosome separation and contributes to genetic diversity in sexually reproducing organisms.
