Meiosis By Mr Meade Body cells and gametes
Meiosis By: Mr. Meade
Body cells and gametes n 2 major groups of cells: gametes and somatic cells. n Somatic cells are cells that make up the tissues and organs in your body. n Gametes are sex cells. – Ova in women – Spermatozoa in men
Body cells and gametes n Each species has a character number of chromosomes in every cell. n Chromosome # doesn’t relate to complexity. n Humans have 46 chromosomes, 23 pairs.
Autosomes and sex chromosomes n Humans have 46 chromosomes, 23 from mom and 23 from dad. n Homologous chromosomes are 2 chromosomes, 1 from each parent, that have the same length and appearance.
Autosomes and sex chromosomes n Scientists have assigned a number to each chromosome based on size from largest to smallest. n Chromosomes 1 -22 make up your autosomes, or chromosomes not related to sex.
Autosomes and sex chromosomes n Sex chromosomes control sexual development. n XX are female n XY are male n The X chromosome is larger, so females contain genes that males are missing.
Diploid and haploid n Sexual reproduction is the process of fusing 2 gametes resulting in offspring. n Fertilization is when the sperm and egg’s nuclei fuse to form one nucleus.
Diploid and haploid n Diploid means a cell has 2 copies of each chromosome, 1 from each parent. n Humans have 46 diploid chromosomes. n Gametes are haploid, meaning each cell has one copy of each chromosome.
Diploid and haploid n So when the sperm and egg fuse, the off spring get 23 chromosomes from each parent. n Maintaining the correct number of chromosomes is important to the survival of each species.
Meiosis n Meiosis is a form of cell division of that divides diploid into haploid cells. n Germ cells (gametes) undergo the process of meiosis.
Meiosis n Homologous chromosomes are 2 separate chromosomes, 1 from each parent. n They carry the same genes, but are not copies of each other.
Meiosis n Homologous chromosomes are divided in meiosis I. n Sister Chromatids are divided in meiosis II.
Meiosis I and II n Both stages of meiosis I and II have the same stages and the same as mitosis. – Prophase – Metaphase – Anaphase – Telophase
Compare and Contrast Mitosis with Meiosis
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