Feature Mitosis Meiosis Purpose Growth & Tissue Repair Production of Gametes
(Sperm/Egg) Location Somatic (Body) Cells Germ (Reproductive)
Cells Daughter Cells 2 Identical Cells 4 Genetically Unique Cells Chromosome Count Diploid (46) Haploid (23)
The Human Cell Cycle Before a cell can divide, it must prepare. This preparation and the division itself are part of the Cell Cycle. Interphase (The Preparation Phase) This takes up about 95% of the cell's life.
G1 Phase (Gap 1): The cell grows and performs normal functions.
S Phase (Synthesis): DNA is replicated. Each of the 46 chromosomes is copied.
G2 Phase (Gap 2): Final growth and protein synthesis before division.
Mitosis: The Equational Division Mitosis ensures that every new cell in your body has the exact same DNA as the original. It consists of four main stages:
Prophase: Chromosomes condense and become visible. The nuclear envelope breaks down.
Metaphase: Chromosomes line up in the middle of the cell (the "metaphase plate").
Anaphase: Sister chromatids are pulled apart to opposite sides of the cell.
Telophase: Two new nuclear envelopes form around the separated chromosomes. Cytokinesis: The cytoplasm pinches in the middle, splitting the parent cell into two separate daughter cells.
Meiosis: The Reduction Division Meiosis is more complex because it reduces the chromosome number by half so that when a sperm and egg meet, the baby has the correct number (46).
Meiosis I: Homologous chromosomes (pairs) separate. This includes Crossing Over, where DNA is swapped between chromosomes to create genetic variety.
Meiosis II: Similar to mitosis, where the sister chromatids finally separate.
Why Is This Important? Growth:
You started as one cell (a zygote). Trillions of mitoses made you an adult. Repair: When you cut your skin, mitosis produces new skin cells to heal the wound. Replacement: Your body constantly replaces old cells (e.g., red blood cells live only about 120 days). Health: If cell division happens too fast or without control, it can lead to cancer.
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