December_Exam

December_Exam - Biology December Exam Dec 16th, 2008...

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Biology December Exam Dec 16 th , 2008 Lecture 12 – Genetic Recombination Inheritance of difference - Mutations in DNA sequence give rise to different versions of a given - Homologous chromosomes may carry different alleles for any given - In meiosis I homologous pairs and then segregate to different daughter - Independent assortment of alleles of homologous in metaphase I - Different set then you have by recombination - Cut/switch/paste recomb during meiosis creates chromatid with novel - Indpt alignment of gametes generates immense diversity of zygotes Independent Assortment – alignment of one allele is indpt of the other, 2 possible Sexual Recombination in Eukaryotes - Homologous haploid parental genomes into close proximity in a diploid - Recomb during meiosis yields cells with diff DNA sequence than carried - DNA repair? Once double stranded cannot change mutation Prophase – crossing over of sister homologous pairs, not just side by side, as much contact as possible (see mechanism of recomb slide 7) Metaphase II - sisters are no longer identical so 2 possibilities, indpt alignment - # of chromosomes remains the same, haplotype daughter cells are not - Life Cycles - n is the # of chromosomes in one basic set (haploid, diploid, . ..), not - product of meiosis in plants is spores - mitosis occurs so there is not genetic variation in gametes - fertilized gametes make zygotes ( half or more of the cycle)
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Lecture 13 – Mendelian Genetics 1 Bacterial Reproduction - binary fission is asexual - popN genetically homogeneous - recomb needs DNA from diff cells to be close in proximity F factor transfer (refer to slide 4) - F+ rolls circle in to F- recipient to become F+ recipient , uses only F - Not antibiotic resistance, only for its own use Bacterial Gene Transfer (refer to slide 4) - DNA (half F & chromosomes) from one cell transfers into new cell that - Sexual reproduction occurs so b+ - the transferred DNA bridge breaks becoming linear so it deteriorates - or F can integrates into DNA and still replicates thinking its only F Transduction by bacteriophage T4 Phage - virus attaches to bacti and injects its DNA, restriction enzyme in bacti cannot cut viral DNA - baby virus chromosomes made so replicates DNA & protein coat - Transduction - Virus injects DNA degrading bacti DNA - A small piece of bacti is mistaken as virus so is put in protein - Bacti DNA virus won’t kill other bacti, transfers gene ( leu+), recipient looses all linear DNA Transformation – ecoli doesn’t naturally get DNA from other cells, need even # of Independent assortment – alleles of gene that combine by themselves, colour
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Mendelian Assumptions – show complete dominance, have only two alleles, coded by one gene, unaffected by environment, carried on autosomes Lecture 14 – Mendelian Genetics 2 Monohybrid – single gene (aa) Explanatory Model - variation in traits due to diff alleles, organisms inherit 2 alleles for each
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December_Exam - Biology December Exam Dec 16th, 2008...

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