dna replication. nucleotides t.h. morgan genes are located on chromosomes
DESCRIPTION
T.H. Morgan Genes are located on chromosomesTRANSCRIPT
DNA Replication
Nucleotides
T.H. MorganGenes are located on chromosomes
Transformation (Griffith 1928)
Avery, McCarty, MacLeod (1944)
Genetic MaterialProtein or DNA ????
"Studies on the chemical nature of the substance inducing transformation of pneumococcal types"
Phages
Hershey & Chase (1952)
Linus Pauling (1948)Alpha Helix Structure
Chargaff’s RuleAdenine – ThymineGuanine - Cytosine
Watson & Crick
Maurice WilkinsX-ray diffraction
Rosalind Franklin
Nucleotides
X-ray Data
DNA Structure
Complimentary Strands
Semiconservative Model
(Meselson & Stahl)
Semiconservative Model(Meselson & Stahl)
Origin of Replication
DNA Nucleosides Triphosphates
Antiparallel
EnzymesDNA PolymeraseHelicaseSingle-strand binding proteinTopoisomeraseRNA primaseLigase
RNA PrimerUses RNA primase to build RNA primerEventually replaced with DNA by DNA Polymerase
DNA Replication
Leading and Lagging StrandsLeading Strand
Built in the 5’-3’ directionBuilt toward the replication forkBuilt continuouslyUses one RNA Primer
Lagging StrandBuilt in the 5’-3’ directionBuilt away from the replication forkBuilt discontinuously using Okazaki fragmentsMany RNA Primers
Overview
ProofreadingMismatch RepairNucleotide Excision Repair (nucleases)
End-replication ProblemNucleotides can only be added to 3’ end
Leaves gap on leading strand
Each replication causes DNA molecule to get smaller
Telomeres
TelomeresEnd of DNA strand made up of reoccurring DNA sequenceCan be rebuilt with telomerase (only in germ-line cells)