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DNA and the CENTRAL DOGMA . Everything you never wanted to know, but still need to understand… and then some more bonus stuff to really make you happy. Transformation of Bacteria. a) Mouse dies. b) Mouse lives. c) Mouse lives.
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DNA and the CENTRAL DOGMA Everything you never wanted to know, but still need to understand… and then some more bonus stuff to really make you happy
Transformation of Bacteria a) Mouse dies b) Mouse lives c) Mouse lives d) Mouse dies. Living S cells are found in blood sample from dead mouse 1928 Fredrick Griffith
3. Centrifuge and measure radioactivity 1. Mix phages with bacteria 2. Blend to mix
What makes up DNA subunits? • 5-carbon sugar • Phosphate • Nitrogenous base
A and G are Purines (double rings) • C and T are pyrimidines (single rings) “Attorney Generals are pure”
DNA REPLICATION DNA polymerase attaches nucleotides to each template strand 2 complimentary strands. A=T C≡G Helicase breaks H bonds and unzips Each “daughter” DNA consists of one parental and one new strand
Conservative – parental helix remains intact; an all new copy is made SemiConservative – two strands separate and each functions as a template Dispersive – each strand contains pieces of old and new DNA
Meselson-Stahl Experiment 1st replication ~20 min 2nd replication ~40 min “new” DNA synthesized would be lighter than the “old” DNA Incorporates heavy nitrogen into DNA Incorporates lighter nitrogen into DNA
Incorporation of nucleotide Enzyme DNA polymerase catalyzes this reaction
DNA Helicase – unzips Topoisomerase – unwind DNA SSBP – single strand binding proteins, hold strands open Primase – joins RNA nucleotides to eukaryotes (primer is required for polymerase to synthesize) DNA Polymerase – adds nucleotides Ligase – link Okazaki fragments
FROM GENE TO PROTEINBeadle and Tatum – one gene, one polypeptide