Which of the following events occurs during interphase of the cell cycle?
options: A) condensation of the chromosomes (they become visible) B) pairing of the homologous chromosomes C) replication of the DNA D) All of the above
The correct answer and explanation is:
The correct answer is C) replication of the DNA.
Explanation:
Interphase is the longest phase of the cell cycle, and it prepares the cell for division. It consists of three main stages: G1 (Gap 1), S (Synthesis), and G2 (Gap 2). Each stage plays a critical role in preparing the cell for mitosis or meiosis.
- G1 phase: During this phase, the cell grows and performs its normal functions. This is the stage where the cell decides whether to divide or not, based on internal and external signals. At the end of G1, the cell is ready for DNA synthesis in the next stage.
- S phase: This is the critical phase for DNA replication. The entire genome of the cell is copied to ensure that both daughter cells will receive an identical set of genetic material. This process is highly regulated and is essential for maintaining genetic integrity during cell division.
- G2 phase: This phase involves additional growth and preparation for mitosis. The cell checks the DNA for errors that might have occurred during replication and repairs them before division.
During interphase, the condensation of chromosomes (A) and the pairing of homologous chromosomes (B) do not occur. These events are part of mitosis (in the case of condensation) or meiosis (in the case of homologous chromosome pairing), both of which happen after interphase. In mitosis, chromosomes condense and become visible, but this occurs in prophase, not interphase. Similarly, pairing of homologous chromosomes occurs in meiosis during prophase I, not during interphase.
Thus, the most accurate event that occurs during interphase is the replication of the DNA. This process is essential for ensuring that each daughter cell will have a complete and identical set of chromosomes after cell division.