HUMAN GENETICS EXAM 2 Chapter 9 Griffiths Bacterial Transformation 1928 o Mouse and bacterial experiment o Two types of bacteria rough coat no pneumonia smooth coat pneumonia o Rough coat lived smooth coat died o Heat killed smooth coat lived o Rough coat and killed smooth coat died with alive smooth coat in blood stream o Coat type is associated with virulence Avery MacLeod and McCarthy o Discovery of the transforming principle was Treated lysed s broken open bacteria with protease and DNAase DNAase prevented transformation or heart killed smooth coat to alive smooth coat and mouse lived Protease did not stop mouse from dying DNA is the transforming principle and kept mouse from dying inhibits protein degrades inhibits DNA prevents o Protease o DNAase transformation from occurring Hershey and Chase pinpointing of DNA as heredity molecule o Used radioactive sulfur and phosphate to label protein and DNA o Sulfur protein coat did not produce radioactive e coli o Phosphorus DNA produced radioactive e coli not the protein carries DNA the genetic info for a new generation Chargaff s rule about DNA bases o With an individual these are paired with hydrogen bonds A T G C o Wilkins and Franklin s photo 51 X ray diffraction of a DNA double helix two twisted DNA strands antiparallel Watson and Crick s DNA Model o A sugar phosphate backbone o Two nucleotide chains in a helix held together by two hydrogen bonds o DNA strands are antiparallel read in opposite way 3 5 right to left 5 4 left to right o Nucleotides Structure of DNA acid building block of a nucleic Consists of a phosphate group nitrogenous base deoxyribose Backbone sugar and phosphate pair Purines A G with o Bases pyrimidines T C A T G C Bound by hydrogen bonds If RNA is present A U o Strands are antiparallel Head to tail position of the entwined chains of double helix One runs 5 3 bottom Other runs 3 5 top o 30 DNA 30 histone 30 DNA protein binding 10 RNA sequences Histone protein that DNA wraps around spool 8 all together Chromatin DNA and its associated histone proteins Condensed to form chromosomes Located in nucleus HUMAN GENETICS EXAM 2 o Replication synthesized DNA formed on the lagging template strand Helicase binds to origin and seperates strands Binding proteins keep strands apart Primase makes a short primer of RNA on the DNA template DNA polymerase adds DNA nucleotides to the RNA primer then checks and replaces incorrect bases Continuous strand synthesis continues in a 5 3 direction Discontinuous synthesis produces Okazaki fragments on the 5 to 3 template Enzymes remove RNA primers and ligase seals sugar phosphate backbone Two new DNA molecules new old DNA replication o Semi conservative new old Each new DNA strand double helix condenses half of the original The parent molecule copies two new molecules each with one strand old and one strand new These split and create two more new strands total of 6 new DNA strands and two original strands Two molecules with one new strand and one old strand two new molecules with both new strands o Enzymes needed Helicase double helix Binding proteins separate strands Primase template strand unwinds parental stabilize the adds short primer to Primer needed because it is the starting point for replication DNA polymerase can only add new nucleotides to an existing strand DNA polymerase binds nucleotides to form new strands Ligase and seals other nicks in sugar phosphate backbone joins Okazaki fragments Okazaki fragment short fragment of DNA capped by the RNA primer at the 5 terminal during replication newly