Answer to Question #325087 in Cell Biology for Isaac

Question

Illustrate/Label Mitosis and Meiosis. Compare and Contrast both explaining Cell Division. Which is Asexual Reporduction and Sexual Reproduction? Why?

Answer 1

Mitosis is asexual reproduction, while meiosis is sexual reproduction. Sexual reproduction means that two haploid cells(gamete) combine  to produce a zygote with a new combination of  characteristics and properties different from parental. The process of haploids cells formation happens exactly during meiosis. Mitosis is a process where a single cell divides into two identical daughter cells (cell division). The major purpose of mitosis is for growth and to replace worn out cells, not development of diversity.

Both mitosis and meiosis start from a diploid parent cell. Both mitosis and meiosis are processes of nuclear division of cells. The major steps of both mitosis and meiosis are interphase, prophase, metaphase, telophase, and anaphase. The DNA of the parent cell is replicated prior to nuclear divisions.

Mitosis: A somatic cell divides once. 

Meiosis: A reproductive cell divides twice.

Mitosis: Two daughter cells are produced. Cells are diploid containing the same number of chromosomes.

Meiosis: Four daughter cells are produced. Each cell is haploid.

Mitosis: The resulting daughter cells in mitosis are genetically identical). No crossing over occur.

Meiosis: The resulting daughter cells contain different combinations of genes. Genetic recombination occurs

Mitosis: During the first mitotic stage, known as prophase, chromatin condenses into discrete chromosomes, the nuclear envelope breaks down, and spindle fibers form at opposite poles of the cell. A cell spends less time in prophase of mitosis than a cell in prophase I of meiosis.

Meiosis: Prophase I consists of five stages and lasts longer than prophase of mitosis. The five stages of meiotic prophase I are leptotene, zygotene, pachytene, diplotene, and diakinesis. These five stages do not occur in mitosis. Genetic recombination and crossing over take place during prophase I.

Mitosis: Tetrad formation doesn’t occur.

Meiosis: Tetrad formation occurs.A tetrad consists of four chromatids.

Mitosis: Sister chromatids align at the metaphase plate.

Meiosis: Tetrads align at the metaphase plate in metaphase I.

Mitosis: During anaphase, sister chromatids separate and begin migrating centromere first toward opposite poles of the cell. A separated sister chromatid becomes known as daughter chromosome and is considered a full chromosome.

Meiosis: Homologous chromosomes migrate toward opposite poles of the cell during anaphase I. Sister chromatids do not separate in anaphase I.