Gamete Formation (Meiosis) Journal 6-5 Gamete Formation (Meiosis)
Meiosis 2 consecutive cell divisions Reduction divisions The number of chromosomes in a cell is halved Forms gametes
Unit 5 - Reproduction (Topics 3-4) Gametes – Sex Cells 23 chromosomes Ex: Sperm and Ovum Zygote – Cell formed from fusion of ovum and sperm 46 chromosomes Fertilized egg Somatic Cells Cells with all 46 chromosomes Body cells Ex: skin cells, muscle cells, nerve cells
Chromosomes in Humans Diploid cells (2n) = 46 or 2 sets of 23 chromosomes 23 from a male gamete (sperm) 23 from a female gamete (ovum) Haploid cells (n) = 23 or 1 set of chromosomes (sperm and egg)
Tetrads 2 Replicated Homologous Chromosomes = 1 Tetrad Replicated sets of chromosomes 2 Replicated Homologous Chromosomes = 1 Tetrad
Meiosis 1 Chromosomes replicate to form tetrads Crossing over occurs Division separates tetrads
Meiosis 2 Division separates sister chromatids
Spermatogenesis Process that forms sperm, the male gamete One diploid cell produces 4 sperm via meiosis
Oogenesis Process that forms ovum, the female gamete One diploid cell produces one ovum