MEIOSIS NOTES

Meiosis A copying process that produces cells with half the usual number of chromosomes as the parent cell. Creates sex cells (sperm & egg)

There are 2 divisions of the nucleus (called meiosis I and meiosis II)

Starts with 1 diploid cell and ends with 4 haploid cells. Diploid: cell that contains pairs of homologous chromosomes. Ex: body cells (46 chromosomes) Haploid: cell with half the number of chromosomes as the parent (diploid) cell Ex: sperm & egg (23 chromosomes) diploid diploid 46 46 46 haploid haploid

**Draw & Label this example Sex Cells (sperm or eggs) Meiosis in Humans **Draw & Label this example 46 (92 when copied) # of chromosomes 1st Division of Nucleus 46 46 2nd Division of Nucleus 23 23 23 23 Sex Cells (sperm or eggs)

**Draw & Label this example Fertilization The joining together of egg & sperm. New cell formed called a zygote. **Draw & Label this example 23 23 sperm egg 46 zygote

Meiosis vs. Mitosis in Humans Creates sperm or egg cells Creates body cells 2 divisions of nucleus 1 division of nucleus Ends with 4 cells Ends with 2 cells Cells have 23 chromosomes Cells have 46 chromosomes Cells are haploid Cells are diploid Sexual Reproduction Asexual Reproduction