BIOSC 150 1nd Edition Lecture 19 Outline of Last Lecture I Genetics II Offspring III Inheritance Outline of Current Lecture 1 Meiosis I 2 Meiosis II 3 Sexual Reproduction Current Lecture Meiosis making haploid gametes Meiosis explains Mendel s principals of segregation and independent assortment Members of gene pair alleles segregate into different gametes Alleles for different genes sort independently of each other into gametes Sexual Reproduction Produce haploid gametes through meiosis Fertilization fusing haploid gametes to form a diploid zygote Mitotic divisions to make many diploid cells that will differentiate and develop a new organism Meiosis makes cells that become sperm or eggs in testes or ovaries Oocytes begin meiosis in fetal ovaries and then stop until puberty 6 12 months Chromosomes do not hang out in pairs like this but Nettie Stevens noticed 2 of each chromosome size shape Number of chromosomes varies in different organisms These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute Homologues have the same genes in same place but often have different alleles of the gene Non homologues chromosomes contain different genes Gametes contain one copy of each chromosome Other cells will contain two DNA replicates before meiosis Recombination sorts some alleles between homologues Homologues pair align and separate in meiosis I Sisters separate in Meiosis II Homologues orient randomly at equator Mating brings the sperm and egg together Mitotic divisions follow gamete nuclei fusion Homologues chromosomes pair line up and separate in Meiosis I
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