Mitosis and Meiosis

  • Created by: farahh24
  • Created on: 12-09-18 20:24
View mindmap
  • Mitosis and Meiosis
  • Mitosis
  • Repair, replacement and growth. Produces two genetically identical daughter cells.
  • Growth 1: Cellular contents duplicated
    • Cell Cycle
    • Synthesis: Chromosomes duplicated
      • Growth 2: Checks duplicated chromosomes for error and makes repairs.
        • Mitosis: Division of nucleus
          • Cytokinesis: Division of cytoplasm.
  • 1. Prophase:
    • Nuclear envelope disintegrates.
  • 3. Anaphase:
    • Chromatids pulled to opposite poles.
      • Spindle fibres contract.
  • 4. Telophase.
    • Forms nuclear envelope.
      • Chromatids have reached poles, now called chromosomes
  • Cleavage furrow forms at middle of cell.
    • Plasma membrane pulled close enough to fuse around middle.
    • Cytokenisis in animals
  • Meiosis
  • Cytokinesis in planes
    • Vesicles from Golgi apparatus assemble at metaphase plate
      • New sections of cell wall form along new sections of membrane
        • Membrane must be formed before cell wall, or cell wall would undergo osmosis lysis.
  • Results in four daughter gametes with half the number of chromosomes
  • Prophase 1:
    • Chromosomes condense, nuclear envelope disintegrates.
      • Homologous chromosomes form bivalents
        • Crossing over: chromatids entangle, breaks off at chiasmata, genetic variation
  • Metaphase 1:
    • Spindle fibres attach to centromeres, homologous pairs line up at metaphase plate
      • Orientation of pairs to either pole is random - independent assortment.
  • Grey= genetic variation
  • Anaphase 1:
    • Homologous pairs pulled to either pole.
  • Telephase 1:
    • Chromosomes assemble at opposite poles, nuclear membrane forms.
  • Prophase 2:
    • Chromosomes condense.
      • Nuclear envelope disintegrates.
        • Centrioles at opposite poles.
  • Metaphase 2:
    • Chromosomes line up at equator.
      • Independent assortment - orientation of chromosomes to either pole is random
  • Anaphase 2:
    • Chromotids of chromosomes pulled to either pole of cell.
  • Telophase 2:
    • Chromatids assemble at poles.
      • Nuclear envelope formed.

Comments

No comments have yet been made

Similar Biology resources:

See all Biology resources »See all DNA, genetics and evolution resources »