Multiple Choice
In sexually reproducing eukaryotes, meiosis begins with which type of cell?
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9. Mitosis and Meiosis
Meiosis
Multiple Choice
During interphase before meiosis I, what key event must occur to ensure each chromosome consists of two sister chromatids?
A
DNA is replicated during S phase, producing sister chromatids for each chromosome.
B
Homologous chromosomes separate into different cells, reducing the chromosome number by half.
C
Sister chromatids separate at the centromere, forming haploid daughter cells.
D
Crossing over occurs between non-sister chromatids, creating chiasmata.
Verified step by step guidance1
Understand that before meiosis I begins, the cell is in interphase, which includes the G1, S, and G2 phases.
Identify that the key event to produce sister chromatids is DNA replication, which occurs during the S phase of interphase.
Recognize that DNA replication duplicates each chromosome, resulting in two identical sister chromatids connected at the centromere.
Note that this duplication is essential because meiosis I will separate homologous chromosomes, but each chromosome must already consist of two sister chromatids.
Recall that other events like homologous chromosome separation, sister chromatid separation, and crossing over occur later during meiosis, not during interphase.
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