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Meiosis and Sexual Reproduction. Chapter 7. Meiosis. Formation of gametes The process of cutting chromosome number in half 2 Divisions Reduction Production . Let’s Make a Gamete : 1. Prophase 1. Chromosomes become visible Nucleus breaks down. Prophase 1: Crossing Over.
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Meiosis and Sexual Reproduction Chapter 7
Meiosis • Formation of gametes • The process of cutting chromosome number in half • 2 Divisions • Reduction • Production
Let’s Make a Gamete : 1. Prophase 1 • Chromosomes become visible • Nucleus breaks down
Prophase 1: Crossing Over • Crossing over occurs • Portions of a chromatid on one homologous chromosome are broken and exchanged with the corresponding portions on the other homologous chromosome
Creates Genetic Diversity !!!!!! Survial of a species
Metaphase 1 • Pairs of chromosomes move to middle of the cell
AnaPhase 1 • Homologous pairs move to opposite ends of the cell
Telophase 1 and cytokinesis • Chomosomes move to end of cell • Cytoplasm divides • Chromosome number cut in half!!!!!!!
Division 2 Meiosis
Prophase II • Happens in both cell at the same time • A new spindle forms
Metaphase II • Chromosomes line up at the equator
Anaphase II • Centromeres divide • Chromosomes move to opposite ends of cells
Telephase II • Nuclear membrane reappears • Cytokinesis • Result: ? • 4 Haploid Gametes • Egg (ovum) • Sperm