Which of the following does not occur during the mitosis phase of the cell cycle?

• A. Formation of the mitotic spindle
• B. Condensation of chromatin into chromosomes
• C. Replication of DNA
• D. Separation of sister chromatids

Answer: (C)

Verified step by step guidance

1. Understand the phases of the cell cycle: The cell cycle consists of interphase and mitotic phase. Interphase includes G1, S, and G2 phases, where the cell grows and DNA is replicated. The mitotic phase includes mitosis and cytokinesis.
2. Identify the key events of mitosis: Mitosis is the process of nuclear division and includes prophase, metaphase, anaphase, and telophase. During these stages, the mitotic spindle forms, chromatin condenses into chromosomes, and sister chromatids separate.
3. Recognize the timing of DNA replication: DNA replication occurs during the S phase of interphase, not during mitosis. This is crucial for understanding why replication of DNA is not part of the mitotic phase.
4. Examine the options given: Formation of the mitotic spindle, condensation of chromatin into chromosomes, and separation of sister chromatids are all events that occur during mitosis.
5. Conclude which event does not occur during mitosis: Since DNA replication occurs during interphase, specifically the S phase, it does not occur during the mitotic phase.