Question

how do meiosis i and meiosis ii differ?
select the two answers that are correct.
□ meiosis i is preceded by dna replication, whereas meiosis ii is not preceded by replication.
□ meiosis i yields four haploid daughter cells, whereas meiosis ii yields two haploid daughter cells.
□ meiosis i yields egg cells, whereas meiosis ii yields sperm cells.
□ meiosis i yields diploid daughter cells, whereas meiosis ii yields haploid daughter cells.
□ meiosis i divides homologous chromosomes, whereas meiosis ii divides sister chromatids.

Explanation:

• For the first option:
• Before meiosis I, DNA replication occurs during the S - phase of interphase. This replication is necessary to duplicate the genetic material so that homologous chromosomes can be separated. In meiosis II, there is no DNA replication before it starts.
• For the second option:
• Meiosis I yields two haploid daughter cells (in terms of chromosome number, as homologous chromosomes are separated). Meiosis II, which is similar to mitosis, takes the two haploid cells from meiosis I and further divides them (by separating sister chromatids) to produce a total of four haploid daughter cells. So this option is incorrect.
• For the third option:
• Both meiosis I and meiosis II are involved in the production of both egg and sperm cells (in different organisms and at different stages of gametogenesis). Meiosis I and II are just stages in the overall process of gamete formation, not specific to egg or sperm production. So this option is incorrect.
• For the fourth option:
• Meiosis I results in haploid cells (because homologous chromosomes are separated). Meiosis II also results in haploid cells (since sister chromatids are separated from the already haploid cells of meiosis I). So this option is incorrect.
• For the fifth option:
• In meiosis I, the main event is the separation of homologous chromosomes. In meiosis II, similar to mitosis, the sister chromatids of each chromosome are separated.

Answer:

• Meiosis I is preceded by DNA replication, whereas meiosis II is not preceded by replication.
• Meiosis I divides homologous chromosomes, whereas meiosis II divides sister chromatids.