Cell Division
Year 9 ๐ฌ Cell Biology & Biochemistry Mitosis, meiosis, and the cell cycle.
๐ Mitosis
Mitosis produces two genetically identical diploid daughter cells. It is used for growth, repair, and asexual reproduction.
Mitosis result
1 diploid cell (2n) โ 2 genetically IDENTICAL diploid cells (2n)| Phase | Key events |
|---|---|
| Interphase (not strictly mitosis) | Cell grows; DNA replication; organelle duplication |
| Prophase | Chromosomes condense and become visible; nuclear envelope breaks down; spindle forms |
| Metaphase | Chromosomes align along the cell equator; spindle fibres attach to centromeres |
| Anaphase | Sister chromatids pulled to opposite poles by spindle fibres |
| Telophase + Cytokinesis | Nuclear envelopes reform; chromosomes uncoil; cell divides into two |
๐ Meiosis
Meiosis produces four genetically different haploid daughter cells for sexual reproduction.
Meiosis result
1 diploid cell (2n) โ 4 haploid cells (n) โ all genetically DIFFERENT- Meiosis I โ homologous pairs separate; crossing over creates new allele combinations
- Meiosis II โ sister chromatids separate (similar to mitosis)
- Results in gametes (eggs and sperm) with unique genetic combinations
- Sources of variation: independent assortment of chromosomes + crossing over
Mitosis vs Meiosis: Mitosis = growth/repair (2 identical diploid); Meiosis = gamete production (4 unique haploid).
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Interactive Demo โ Cell Division
Cell Cycle Calculator