Meiosis

• Normal body cells are known as diploid calls.
• Diploid cells contains two copies of each chromosome. this means that they have two copies of each gene.
• Diploid cells in humans contain 46 chromosomes (23 pairs.)
• egg and sperm cells are haploid cells.
• Haploid cells only have one of each chromosome
• Haploid cells in humans contains 23 chromosomes. these cells are called gametes
• Games are produced by meiosis.
• in mammals, meiosis is important as it increases the genetic variation
• division 1: before the cells start to divide the DNA is replicated. the chromosomes line up in pairs in the center of the cell. the arrangement is random, leading to variation. the pairs are then separated. some of the father chromosomes and some of the mother chromosomes go into each new cells. the chromosome number is halved at this point.
• Division 2: in the second division, the chromosomes line up again in the center of the cell. the chromosomes splits and the chromatids (arms) of the chromosomes are pulled apart, producing 4 daughter cells. each daughter cell is haploid and genetically different.
• stages of meiosis