Unit 3 DNA

Unit 3 DNA - terms and concepts in unit 3 classes 17-18...

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terms and concepts in unit 3 classes 17-18 genetic transformation: what is it and how was it used by Griffith and Avery to show that DNA is the genetic material uptake of DNA into living cells and inheritance causes genetic change Griffith : used pathogenic strain of S. pneumonia in mice and observed effects: how did the information making the bacteria pathogenic get transferred from the dead cells to the live coatless cells? Avery : determined if hereditary information was protein or DNA; removing the proteins didn’t stop the rate of transformation; 1. Chemicals agreed with DNA’s chemicals. 2. Same density as DNA when centrifuged. 3. Removing lipids and proteins didn’t stop it from working. 4. Enzymes that digest proteins didn’t digest substance. 5. DNA-digesting enzyme broke down substance. DNA structural elements: Nucleotides : five carbon sugar (deoxyribose or ribose), phosphate group (PO 4 ), nitrogenous base (purines: guanine or adenine; pyrimidine: thymine or cytosine) sugar-phosphate backbone : repeating phosphate groups and sugar units connected by phosphodiester bonds antiparallel strands : One strand runs 5’ to 3’ and other runs 3’ to 5’ 5’ to 3’ is leading strand; replicated normally 3’ to 5’ is lagging strand; broken into Okazaki fragments and then rebuilt 5’: ends in PO 4; has methyl group 3’: ends in OH - base pair: connection formed by dehydration synthesis; hydrogen bonds Chargaff s rules: Guanine only bonds with Cytosine; Thymine only bonds with Adenine; G and C are present in equal amounts; T and A are present in equal amounts. Equal proportions of purines and pyrimidines. adenine forms two hydrogen bonds with thymine; guanine forms three hydrogen bonds with cytosine hydrogen bonding: makes base pairs connect; strongest of all chemical bonds templates in nucleic acid synthesis: base sequences are complementary making duplication possible semiconservative model of DNA replication: the DNA molecule is unzipped and separated, then complementary bases are added to exposed single strands, forming two daughter strands connected to two original strands. Meselson-Stahl experiment: two bacteria were grown in different isotopes of Nitrogen making each have different densities, then the two were combined and the densities of the DNA were recorded. The densities were intermediate between the two original densities, proving the semiconservatice model is correct. Proteins of DNA replication: Helicase: opens DNA helix; employs energy from the hydrolysis of ATP to unwind the helix single-strand binding protein: connects to single stranded DNA to stabilize and prevent from reconnecting with the other strand. DNA polymerases:
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This note was uploaded on 04/18/2008 for the course BIO 102 taught by Professor Haworth during the Spring '08 term at Marquette.

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Unit 3 DNA - terms and concepts in unit 3 classes 17-18...

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