cell division

• mitosis purpose

  • asexual production
  • identical daughter cells for growth + repair
• stages of mitosis

  1. prophase
  2. metaphase
  3. anaphase
  4. telophase
• cytokinesis

  • parent organelles and replicated organelles move to opposite sides of cells
  • cytoplasm divides to produce two identical daughter cells
• interphase

  • cell grows + prepares to divide
  • organelles +chromosomes replicated - chromosomes begin to condense
• prophase

  • nuclear envelope breaks down -disappears
  • chromosomes condense + centrioles move to opposite poles of cell for spindle formation
• centrioles

  • small, cylindrical structures made of microtubules
  • usually in pairs at right angles near the nucleus
  • help organise the spindle fibres that separate chromosomes during mitosis and meiosis
• metaphase

  • chromosomes arranged along cell equator
  • chromosomes attach to spindle fibres via centromeres
• anaphase

  • sister chromatids pulled to opposite ends
• telophase

  • nuclear envelope + nucleolus reforms
  • chromosomes uncoil
• what is the function of the centromere?

  holds sister chromatids together and attaches to spindle fibres
• spindle fibres

  • protein structures made of microtubules
  • form during cell division
  • organised by centrioles or the microtubule organising centre
  • attach to the centromeres of chromosomes via kinetochores.
  • pull chromosomes apart