Meiosis

• Meiosis

  A type of cell division that produces four haploid gametes, each with a single set of chromosomes, and creates genetic variation in the offspring
• Meiosis is different to mitosis because it doesn't produce identical cells
• Meiosis only happens in the reproductive organs (ovaries and testes) in humans
• Before the cell starts to divide, it duplicates its DNA (so there's enough for each new cell)
• 1. shaped chromosome


  One arm is an exact copy of the other arm
• First division in meiosis

  1. Chromosomes line up in pairs in the centre of the cell

  2. Pairs are pulled apart, so each new cell only has one copy of each chromosome

  3. Some of the father's chromosomes and some of the mother's chromosomes go into each new cell
• First division in meiosis

  • Each new cell will have a mixture of the mother's and father's chromosomes
  • Mixing up the genes like this is really important, it creates genetic variation in the offspring
• Second division in meiosis

  1. Chromosomes line up again in the centre of the cell

  2. The arms of the chromosomes are pulled apart
• You get four haploid gametes - each only has a single set of chromosomes
• The gametes are all genetically different