cell cycle

• interphase of mitosis

  g1, cell growth and make organelles.

  s, DNA synthesis. DNA duplicates ready for division.

  g2, cell growth continues, preparations made like making proteins
• mitosis (nuclear division)

  P (prophase/prepare), chromosomes condense (not tangled up when moving) and nuclear envelope breaks down. Centrioles move to opposite poles and spindle fibres begin to form.

  M (metaphase/meet), chromosomes attach to spindle fibres by centromeres. lined up by equator.

  A (anaphase/apart) sister chromatids separate. spindle fibres shorten and pull chromatids to opposite poles.

  T (telophase/two), chromosomes decondense and envelope forms around each group of chromosomes. spindle fibres break down
• cytokinesis

  protein filaments tighten around cell centre to make 2 cells (animal) or synthesize new cell plates down the middle of the line (plants).
• importance of cell division

  • increase cell number for growth
  • replace damaged/dead cells
  • asexual reproduction
  • produce 2 genetically identical offspring from parents that have a diploid nucleus.