Mitosis and the Cell Cycle

Mitosis and the Cell Cycle

  • The cell cycle is a process by which a cell duplicates its DNA and divides to produce two identical daughter cells. This process includes interphase and the mitotic phase.

  • Interphase is the first stage of the cell cycle. During this phase, the DNA within the cell replicates itself in preparation for mitosis.

  • The cell’s DNA exists in a thread-like form called chromatin during interphase.

  • Interphase includes three stages: G1 Phase (growth), S Phase (DNA synthesis), and G2 Phase (prep for mitosis).

  • Mitosis is composed of four stages: prophase, metaphase, anaphase, and telophase.

  • Prophase is the initial phase of mitosis. Here, the DNA condenses to form chromosomes, and the nuclear envelope breaks down.

  • Metaphase follows prophase. The chromosomes line up in the middle of the cell, held by spindle fibres attached to the centromeres.

  • Anaphase comes next. The pairs of sister chromatids are separated by the spindle fibres and pulled to either end of the cell.

  • Telophase is the last phase. A new nuclear envelope forms around each set of chromosomes at either end of the cell.

  • Cytokinesis is the final step in cell division. The cell’s cytoplasm divides, resulting in the formation of two new cells each with the same number of chromosomes as the parent cell. This completes the cell cycle.

  • The new cells go through a period of growth and DNA replication (Interphase) before they can undergo Mitosis again.

  • Mitosis is crucial for growth, repair, and asexual reproduction in organisms.

  • Mutations can occur during DNA replication, leading to variation. Mitosis provides some protection against mutation because it produces clones.

  • Anomalies in the cell cycle can lead to uncontrolled cell division, which is the basis of cancer.

  • Understanding cell division through mitosis is key to comprehending and evaluating biological concepts like growth, asexual reproduction, healing, and disease (specifically cancer).