Cell Division: Mitosis II - Lecture 24

Cell Cycle

• Cell cycle consists of interphase and M phase (mitosis and cytokinesis)
• Interphase is the stage where the cell grows and prepares for cell division
• M phase is the stage where the cell divides to produce two new cells

M Phase

• M phase involves both mitosis and cytokinesis
• A cell divides to produce 2 new cells, genetically identical to the original
• The original cell is called the mother/parent cell, while the new cells are called daughter cells

Mitosis

• Mitosis is divided into 4 phases: prophase, metaphase, anaphase, and telophase
• Though divided into phases, mitosis is a continuous process

Prophase

• Chromosomes condense (shorten and thicken)
• Nuclear envelope breaks down
• Centrosomes travel to opposite poles of the cell to form the spindle

Metaphase

• Chromosomes line up in the middle of the cell
• Each chromosome takes one spindle fibre

Anaphase

• Chromatids break apart at the centromere and move to opposite poles
• Each chromatid becomes an individual chromosome, identical to the original parent chromosome

Telophase

• Chromosomes have reached their respective ends/poles and de-condense
• Nuclear membranes re-form to produce 2 separate nuclei

Cytokinesis

• Process of cytokinesis is different in animals and plants
• In animals, cleavage furrow forms, and a contractile ring consisting of actin filaments forms a constriction, separating the 2 daughter cells
• In plants, a cell plate forms, and a cell wall forms between the two daughter cells

Cell Cycle and Cancer

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