Chapter 14 Notes

Chapter 14 Notes - Structure of Nucleotides: nitrogen base,...

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Structure of Nucleotides: nitrogen base, a phosphate group, pentose (5 carbon sugar) Nitrogenous bases in DNA: purine: double ring structure – Adenine and Guanine pyrimidine: single ring structure – Thymine and Cytosine Nitrogenous bases in RNA: Thymine is replaced by Uracil Griffith’s experiment: Transformation of Bacteria: Streptococcus pneumonia S strain – mouse died: virulent, has a mucous capsule and forms “shiny” colonies R strain – mouse lived: not virulent, no capsule and forms “dull” colonies Heat-killed S strain – mouse lived: determine whether capsule was responsible for virulence S strain: encapsulated R strain: non-encapsulated Griffith concluded that some substance necessary for synthesis of capsule – and therefore for virulence – must pass from dead S strain bacteria to living R strain bacteria so that R strain were transformed change in phenotype of R strain must be due to a change in bacterial genotype transforming substance passed from S to R strain Meselson and Stahl ‘s experiment: confirmed DNA replication is semiconservative Cell grown in heavy nitrogen 15N have dense strands (HEAVY DNA) DNA after one division in light nitrogen 14N, DNA molecules are hybrid and have intermediate
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This note was uploaded on 01/30/2010 for the course BIOL 1 taught by Professor Iwanaga during the Fall '08 term at Mt. SAC.

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Chapter 14 Notes - Structure of Nucleotides: nitrogen base,...

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