Homologous Chromosomes: Pairs of chromosomes that contain the same set of genes in the same order. Haploid Cells: Cells that contain only one copy of each chromosome. Crossing Over: The process in which homologous chromosomes exchange genetic material during meiosis.
Humans have 23 pairs of homologous chromosomes. Homologous chromosomes have the same genes along their length. 23 chromosomes come from the mother in an egg, and 23 from the father in a sperm. When fertilisation takes place a new individual is formed with 46 chromosomes.
Purpose of Meiosis
Sex cells are called gametes. Body cells are called somatic cells. These are formed by mitosis. Somatic cells are diploid. They have two sets of homologous chromosomes. Mitosis forms two identical diploid daughter cells. Gametes are haploid. They have half the number of chromosomes of a somatic cell. Meiosis forms four different haploid daughter cells.
Meiosis is a type of cell division that produces haploid cells with half the number of chromosomes as the parent cell. It involves two rounds of cell division, meiosis I and meiosis II, and is essential for sexual reproduction. In meiosis I, homologous chromosomes pair up and cross over each other to form new combinations of genes.
Meiosis: The Process of Cell Division
Interphase I Prophase II Prophase I Metaphase II Metaphase I Anaphase II Anaphase I Telophase II Telophase I Cytokinesis
Stages of Meiosis
What is the most important outcome of meiosis?
- A) The production of gametes with half the genetic material of the parent
- B) The production of genetically identical cells
- C) The production of new genetic combinations
Draw / write: What is the role of meiosis in sexual reproduction?
Draw / write: How does genetic information from both parents get passed on to offspring?
How does meiosis ensure that genetic information from both parents is passed on to offspring?