Presentation on theme: "Growth, Repair, and Reproduction"— Presentation transcript:
1 Growth, Repair, and Reproduction Mitosis and MeiosisGrowth, Repair, and Reproduction
2 Some vocabulary to know Somatic cell: a body cell having the full complement of Chromosomes (humans = 46)Diploid: having the full complement of chromosomes, both members of each pair (2N)Gamete: a sex cell, like egg, sperm, pollen, having only one of each of the paired chromosomes from an organism. (humans =23)Haploid: having half the complement of chromosomes, one of each pair (1N)
3 MitosisPurpose: to produce new cells for growth or repair of body tisuse.Triggered when cell gets too large, or when cell senses a space nearby (like in a cut).Outcome: 2 daughter cells that are identical clones of original somatic cell.In humans: one cell with 46 chromosomes produced 2 daughter cells each having 46 chromosomes.
4 The Stages of MitosisAs interphase ends, cell is large and has duplicated its DNA. The DNA strands are holding onto their copies.PROPHASE: chromosomes holding onto their copies become visible, nuclear membrane dissolvesMETAPHASE: chromosomes line up at middle of the cell, spindle fibers connected to centromeresANAPHASE: spindle fibers separate each chromosome form its copy, pulling the copies to opposite polesTELOPHASE: reverse of prophase: nuclear membrane reforms, chromosomes loosen and become less visible
5 Meanwhile back at the gonads…. Mitosis will occur, but certain cells will be triggered to continue into meiosis to form sex cells.
6 Crossing Over occurs in Meiosis Crossing Over increases diversity in species , it mixes up the genes that came from your parents so the same traits don’t always get inherited together.