Question

question 6 of 10
what happens to the chromosomes of diploid parent cells during meiosis?
a. homologous chromosomes are replicated to form tetrads, which are grouped together in four new daughter cells.
b. homologous chromosomes are separated, and then sister chromatids are replicated to double their number.
c. the chromosomes are replicated twice to produce four identical copies in the daughter cells.
d. the chromosomes are divided twice: first by separating pairs of homologous chromosomes, and then by separating sister chromatids.

Explanation:

Meiosis is a type of cell division. In meiosis, diploid parent cells divide. First, pairs of homologous chromosomes are separated (meiosis I). Then, sister chromatids are separated (meiosis II). This results in four non - identical haploid daughter cells.

• Option A: Homologous chromosomes form tetrads (during prophase I of meiosis I), but they are not grouped into four new daughter cells in that way. Also, replication occurs before meiosis (in S - phase, not during meiosis in the way described here).
• Option B: Sister chromatids are not replicated during meiosis. Replication occurs before meiosis (in S - phase). And homologous chromosomes are separated in meiosis I.
• Option C: The chromosomes are replicated once (before meiosis in S - phase), and the daughter cells are not identical (due to crossing over and independent assortment).
• Option D: Meiosis involves two divisions. In meiosis I, homologous chromosomes are separated. In meiosis II, sister chromatids are separated.

Answer:

D. The chromosomes are divided twice: first by separating pairs of homologous chromosomes, and then by separating sister chromatids.