Meiosis Study Guide, Overview and Diagrams

Meiosis Study Guide, Overview and Diagrams Overview of Meiosis Meiosis is a two-part cell division process in organisms that sexually reproduce. Meiosis produces gametes with one half the number of chromosomes as the parent cell. In some respects, meiosis is very similar to the process of mitosis, yet it is also fundamentally different from mitosis.The two stages of meiosis are meiosis I and meiosis II. At the end of the meiotic process, four daughter cells are produced. Each of the resulting daughter cells has one half of the number of chromosomes as the parent cell. Before a dividing cell enters meiosis, it undergoes a period of growth called interphase.During interphase the cell increases in mass, synthesizes DNA and protein, and duplicates its chromosomes in preparation for cell division. Meiosis I Meiosis I encompasses four stages: Prophase I - chromosomes condense and begin migrating toward the metaphase plate. Metaphase I - chromosomes align at the metaphase plate. Anaphase I - homologous chromosomes separate and move toward opposite cell poles. Telophase I - cytoplasm divides producing two cells with a haploid number of chromosomes. Sister chromatids remain together. Meiosis II Meiosis II encompasses four stages: Prophase II - chromosomes begin migrating to the metaphase II plate. Metaphase II - chromosomes align at the metaphase II plate. Anaphase II - sister chromatids separate and begin moving to opposite ends of the cell. Telophase II - new nuclei form around daughter chromosomes and the cytoplasm divides. At the end of meiosis II, four daughter cells are produced. Each of these resulting daughter cells is haploid. Meiosis ensures that the correct number of chromosomes per cell is preserved during sexual reproduction. In sexual reproduction, haploid gametes unite to form a diploid cell called a zygote. In humans, male and female sex cells contain 23 chromosomes and all other cells contain 46 chromosomes. After fertilization, the zygote contains two sets of chromosomes for a total of 46. Meiosis also ensures that genetic variation occurs through genetic recombination that happens between homologous chromosomes during meiosis. Stages, Diagrams, and Quiz OverviewStages of MeiosisMeiosis DiagramsGlossary of TermsQuiz Next Stages of Meiosis