Replication of each chromosome and its centromere takes place during which phase of the cell cycle?

• A. G2 phase
• B. M phase
• C. G1 phase
• D. S phase

Answer: (D)

Verified step by step guidance

1. Understand the cell cycle phases: The cell cycle consists of several phases, including G1, S, G2, and M phases. Each phase has specific functions related to cell growth and division.
2. Identify the function of the S phase: The S phase, or synthesis phase, is where DNA replication occurs. During this phase, each chromosome is duplicated, resulting in two sister chromatids connected by a centromere.
3. Differentiate between the phases: G1 phase is primarily for cell growth and preparation for DNA replication. G2 phase involves further growth and preparation for mitosis. M phase is where mitosis and cytokinesis occur, leading to cell division.
4. Recognize the importance of centromere replication: During the S phase, not only is the DNA replicated, but the centromere is also duplicated to ensure proper chromosome segregation during cell division.
5. Conclude the correct phase for replication: Based on the functions of each phase, the replication of chromosomes and their centromeres occurs during the S phase of the cell cycle.