chapters 9-12 - minor

chapters 9-12 - minor - Chapter 9 DNA the molecule of...

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Chapter 9 DNA: the molecule of heredity How did scientists discover that genes are made of DNA? Avery, MacLeod, and McCarty o What is the transforming material? Treated cell extracts with protein, carbohydrate, RNA and DNA digesting enzymes Only cell extracts treated with DNA-digesting enzymes lost their transforming ability DNA transforms bacteria What is the structure of DNA? Nucleotide bases in DNA o Nucleotides contain a phosphate, deoxyribose sugar, and N-containing bases o A nucleotide strand Always assembled from the P end to the S end Covalent bond b/t the sugar of one nucleotide and the phosphate of a second o Watson-crick model of DNA structure Double helix of 2 nucleotide strands Complementary bases pairs hold the 2 nucleotide strands together Complementary strands run in opposite directions o Base pairing in DNA Chargaff’s rule A-t C=g Adenine and thymine always form pairs 2 hydrogen bonds Cytosine and guanine always form pairs 3 hydrogen bonds X-ray diffraction o Maurice Wilkins and Rosalind Franklin knew that DNA formed some sort of helix by the patterns seen in x-ray diffraction The discovery of DNA o Pauling o Wilkins and Franklin o Watson and Crick Genetic Code o One DNA strand Order of nucleotides determines order of amino acids in proteins DNA can encode a lot of information o DNA: A,C,T, and G codes for everything How does DNA replication ensure genetic constancy? DNA structure explains how it duplicates
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o DNA Nucleotide stands held together by hydrogen bonds o Hydrogen bonds are easily broken o Each single strand serves as template for new strand DNA replication o Separate parental DNA helix o Incorporate complementary nucleotides o 2 daughter helices 1 old strand 1 new strand Semi conservative replication Replication enzymes o DNA helicase- unwinds the two strands breaks the hydrogen bonds holding them together o DNA polymerase – attaches complementary o DNA ligase – fills in gaps Continuous and discontinuous assembly o Strands can only be assembled in the P to S direction o DNA ligase fills in gaps on discontinuous strand Chapter 10 Gene expression and regulation How does DNA determine physical characteristics? o
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This note was uploaded on 11/29/2011 for the course BIOL 1001 taught by Professor Minor during the Fall '08 term at LSU.

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chapters 9-12 - minor - Chapter 9 DNA the molecule of...

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