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Chapter 13. Meiosis and Sexual Life Cycles. Parent. Bud. 0.5 mm . Interphase. Homologous pair of chromosomes in diploid parent cell. Chromosomes replicate. Homologous pair of replicated chromosomes. Sister chromatids. Diploid cell with replicated chromosomes. Meiosis I. 1.
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Chapter 13 Meiosis and Sexual Life Cycles
Parent Bud 0.5 mm
Interphase Homologous pair of chromosomes in diploid parent cell Chromosomes replicate Homologous pair of replicated chromosomes Sister chromatids Diploid cell with replicated chromosomes Meiosis I 1 Homologous chromosomes separate Haploid cells with replicated chromosomes Meiosis II 2 Sister chromatids separate Haploid cells with unreplicated chromosomes Figure 13.7 Overview of meiosis: how meiosis reduces chromosome number
Moss life cycle animation. • http://www.sumanasinc.com/webcontent/animations/content/moss.html
Meiosis Animations • http://highered.mcgraw-hill.com/olc/dl/120074/bio19.swf
Pearson Meiosis Lab Print out answers to Lab Quiz 2 tonight
Comparison of Mitosis and Meiosis • http://highered.mcgraw-hill.com/olc/dl/120074/bio17.swf
Independent Assortment Animation • http://highered.mcgraw-hill.com/olc/dl/120074/bio18.swf • http://www.sumanasinc.com/webcontent/animations/content/independentassortment.html
Determination of Possible Chromosome Combinations in each gamete 2N • N= haploid number
Independent Assortment • New cells are not identical to each other • Each cell has different combinations of chromosomes in them - one from each homologous pair of chromosomes • There are >8 million chromosome combinations to make each sperm or egg cell
Sexual Recombination • Creates a greater diversity of individuals in the next generation • It involves three major processes • Crossing Over • Independent Assortment • Gametic Assortment
Gametic Assortment • Each of the >8 million possible sperm cells could combine with one of the >8 million possible egg cells to form a baby • By sexually combining a sperm with an egg, there are >70 trillion possible sperm-egg combinations in each human mating • This is why you don’t look exactly like your brother or sister, even if you had the same parents
>8Million >70 Trillion >8Million
1. What happens during crossing over? Some genetic material is exchanged between two chromatids of homologous chromosomes.