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   Animal Body
   Arthropods
   Biochem
   Cell Cycle
   Cell Interactions
   Cell Structure
   Circulation Respiration
   Communities
   Digestion
   DNA
   Ecosystems
   Energy
   Evolution Evidence
   Future of Biosphere
   Genetic Engineering
   Gene Function
   Genetics
   Hormones
   Human Evolution
   Immunity
   Species Interaction
   Kidneys
   Locomotion
   Membranes
   Mollusks
   Mutation
   Nervous
   Non-Coelmic
   Photosynthesis
   Plant Physiology
   Population Genetics
   Population Dynamics
   Cellular Respiration
   Sensory
   Speciation
   Taxonomy
   Vertebrates
   Vertebrate Org
Vocabulary:
   1,2,3,4,5,6,7,8,9,10,
   11,12,13,14,15,
   16,17,18,19,20,
   21,22,23,24,25,
   26,27,28,29,30,
   31,32,33,34,35,
   36,37,38,39,40,
   41,42,43,44,45,
   46,47,48,49,50,
   51,52,53,54

DNA: The Genetic Material

Hammerling -
Acetabularia (green algae)Cut off different parts of algae

Regrew from footNot regrown from cap or stalk

 

Noticed that nucleus was in the foot so that "hereditary information" must be in nucleusConfirmed by Briggs & King using transplanted nuclei (microdissection)Confirmed by Stewart & Gordon

"totipotency" - all cells contain the full instructions for developmentAnimals lose the ability to access this information after a certain point in development

Griffith / Avery -
"Transforming Principle"Chromosomes / DNA were hereditary informationConfirmed DNA was hereditaryGriffith - pneumonia bacteria w/ Mice
Live Virulent ~> DiedHeat Killed ~> LivedLive No Coat ~> LivedHeat Killed & No Coat ~> Died
Avery -
Dissolved 99.9% of all protein from chromosomesHeredity was "NOT" affected
Hershey / Chase -
Viruses use DNA to direct their activitiesBacteriophage - virus that attacks bacteriaLatch on, inject DNA, cause cell to make multiple copies of viral DNACells lyses, viruses are releasedLabeled DNA w/ 32^P & the coat w/ 35^SAgitated before lysing and recovered 35^SNew viruses had DNA that was 32^P
Frankel / Conrat -
Some viruses use RNA as genetic material ("Retroviruses")Inject RNA, an "intermediate" DNA is formed, then new copies of DNA are made
DNA Chemistry / Structure -
Miescher - structure of nucleotides
PO₄5 carbon sugarNitrogenous base (A, T, C, G)
Repeated units string in a long chainSlightly acidic & very negative (PO₄^-)

PO₄ from one nucleotide & the extra -OH from another nucleotide come together to form bonds by dehydration synthesis. This forms a phosophodiester bond. (phosophate linked to two sugars).This means that DNA always has 5' & 3' endsThis allows for strings of nucleotides (backbon         e) - provides stability & directionalityChargaff's Rules -
A ~> TG ~> Cpurines = pyrimidines
Structure -
X-ray Crystallography allowed discovery of the "Double Helix" - 1954 - Watson & Crick / Franklin
Double Helix -
.34nm between nucleotide3.4nm for one full turn of helix2nm throughout for diameter
Base Pairs -
Hydrogen bonds form between purines & pyrimidinesPlanar & hydrophobically stackedStabilizes the double helixCreates anti-parallel strandsA - T = 2 H-bondsG - C = 3 H-bonds
DNA Replication -
Occurs during SComplimentary - every chain determines the sequence of it's partner in a duplexSemi-conservative - each strand of DNA becomes part of the new duplexProven by: Meselson & Stahl
Grew bacteria in a ¹⁵N (heavy) & ¹⁴N (light)¹⁵N bacteria was put into ¹⁴N mediumFirst Replication - all in same placeAll others - found separation
Replication occurs in opposite direction on the DNA molecule at specific nucleotide sequences called Origins of ReplicationOrigin of Replication is the site at which DNA is unzipped & then stabilized by Helicase!This forms replication bubbles (Actual Replication occurs at the Replication fork)Eukaryotes - 8 hrs (w/out many sites - 800hrs)
Prokaryotic vs. Eukaryotic -
Prokaryotic
Single O.R.Single replication bubbleAdvances in opposite directions until they meet
Eukaryotic
Multiple replication sites (each has its own O.R.)There can be many active sites at onceAdvantage ~> 8hrs to 800hrsSophisticated inhibitors & regulators that ensure construction of one complete, orderly copy

DNA polyermase adds nucleotides to complimentary strand of DNA in the 5' to 3' direction ONLY!Lagging strand needs RNA primers to begin (10 N.T)b/c DNA is antiparallel, replication must work in opposite directionsLeading Strand
One N.T. at a timeTowards replication forkContinuous
Lagging Strand
Away from replication forkDiscontinuousShort DNA fragments called Okasaki fragments (1000-2000 N.T.)When you reach the 5' end of the strand, O.   F. are ligated to it w/ LigaseSo overall, DNA replication is semi-discontinuous
Genes
Garrod
What is encoding?Alkaptonuria – “black urine” oxidation of metabolits as they hit the air (homogenistic acid)Could not break down due to lack of enzymeLooked at pedigree histories & found that it seemed to be a recessive alleleSuggests
Since inherited, it must involve DNASince it is a lack of an enzyme, DNA must code for enzymes
Inborn errors of Metabolism
Tay SachsPKULactose Intolerance
Beatle & Tatum
Set out to prove that genes encode for enzymesExperiment – Neurospora (bread mold)
Grew in complete mediaCreated mutants w/ X-raysGrew offspring on complete mediaTried growing mold on different minimal media that had a particular nutrient added**One gene-one enzyme theory**
Sanger
Studied insulinDetermined AA sequence for the entire moleculeImportance:
All proteins have AA sequence\Enzymes are proteins\Enzymes have a specific AA sequence\Enzymes are encoded by genes\Genes encode for AA sequences
Ingram
Contrib.:  Sickle cell is caused by a single AA replacement (glutamic acid to valine)Imprt: AA sequence is determined by info on the genes

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