Reproduction

• sexual reproduction involves the fusion of male and female gametes


  .
• asexual

  only one parent

  genetically identical to parents

  happens by mitosis

  no fusion of gametes no mixing of chromosomes and no genetic variation
• meiosis

  1. duplicates its genetic info forms two armed chromosomes then arrange themselves into pairs
  2. first divsion-line up in the centre of the cell
  3. then pull apart so each new cell has a copy of the chromosomes
  4. second division-line up ahain arms of the chromosome are pulled apart
  5. have four gametes
• x and y chromosomes

  • 23 pairs kf chromosomes in every human