A cell preparing to undergo meiosis duplicates its chromosomes during
A. prophase I.
B. anaphase I.
C. meiosis II.
D. interphase.
E. metaphase I.
The Correct Answer and Explanation is:
The correct answer is D. interphase.
Meiosis is a type of cell division that reduces the chromosome number by half to produce gametes (sperm and eggs). The process occurs in two stages: meiosis I and meiosis II. Before meiosis begins, however, the cell undergoes interphase, which is a preparatory phase where the cell’s genetic material is duplicated.
Explanation:
Interphase is the phase of the cell cycle during which the cell prepares for division. It is divided into three stages:
- G1 phase (first gap phase) – The cell grows and performs normal metabolic functions.
- S phase (synthesis phase) – The DNA is replicated, meaning the chromosomes duplicate to form two identical chromatids for each chromosome.
- G2 phase (second gap phase) – The cell continues to grow, and the proteins necessary for cell division are synthesized.
The duplication of chromosomes occurs during the S phase of interphase, not during meiosis itself. At this point, each chromosome is made up of two sister chromatids connected by a centromere.
Once interphase is complete, the cell enters meiosis I, which begins with prophase I. During prophase I, the homologous chromosomes (chromosomes with the same genes but possibly different alleles) pair up, undergo crossing-over (exchange of genetic material between homologs), and prepare for the separation of homologous chromosomes. However, no chromosome duplication occurs during this phase, as that process already occurred in interphase.
During meiosis II, the sister chromatids are separated, but there is no chromosome duplication during this stage, as the chromosomes were already duplicated in interphase.
Thus, interphase is the phase where chromosome duplication occurs, providing the necessary genetic material for the subsequent steps of meiosis.