Wk 4 Lec 1s

Wk 4 Lec 1s - Whatwerewetalkingabout?...

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What were we talking about? Factors that affect cell division The cell cycle What happens when the cell cycle is out of control Cancer
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Sexual Cellular Reproduction The Cell Cycle
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Why Reproduce Sexually Mitosis produces clones of genetically identical offspring Meiosis (sexual reproduction) shuffles genes around Even simple prokaryotes have evolved a method to exchange  genetic information, therefore the benefits of sexual  reproduction must be enormous Sexual reproduction combines genetically determined traits
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Homologous Chromosomes Eukaryotic chromosomes  have characteristic shapes, sizes  and staining patterns A view of an entire set of chromosomes is a  karyotype whic h de m o ns tra te s  tha t no n-re pro duc tive  c e lls   have  c hro m o s o m e s  in pairs  tha t s a m e  le ng th  and s ta ining  pa tte rn This happens because each carries the same genes in same  order   homologous chromosomes,  each homologue comes  from a different parent Diploid : c e lls  tha t ha ve  pa irs  o f ho m o lo g o us   c hro m o s o m e s Chromosomes with similar appearance are called  autosomes Sex chromosomes  (X a nd Y) a re  diffe re nt in s ha pe  a nd s ize   Haploid : c e lls  tha t c o nta in o nly o ne  o f e a c h type  o f c hro m o s o m e  (g a m e te ) The number of different types of chromosomes is characteristic of a species and is termed n : equal to  the haploid number of the species
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Homologous chromosomes carry different versions of genes.  Simplified examples: coat color and eye color in mice. C (agouti 5 brown) and c (white) for different versions of the coat-color gene and E (black) and  e (pink) for different eye-color genes. In this example, with the information up to this point, there would be two possible outcomes  for the genes on the two chromosomes in a gamete (2 1 )
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MEIOSIS Meiosis separates homologous chromosomes and  produces  haploid  daughter cells Has features in common with mitosis Important difference is that there is one round of  replication followed by 2 divisions (Meiosis I and 
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This note was uploaded on 10/17/2011 for the course ECON 212 taught by Professor Ffa.de during the Spring '11 term at Drexel.

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Wk 4 Lec 1s - Whatwerewetalkingabout?...

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