PowerPoint Presentation
DNA REPLICATION
1Central Dogma of Genetics: DNA RNA Protein
NuclearmembraneTranscriptionRNA
ProcessingTranslationDNAPre-mRNAmRNARibosomeProteinEukaryotic
Cell3
Each new DNA molecule will be an exact copy of the originalDNA
ReplicationKey to replication is complementary structure of the two
strandsReplication is semiconservative new strands composed of one
original strand and one daughter strand4Untwisting and replication
of DNA each strand is a template for a new strandFigure 10.4B
helicaseDNA polymerase55Initial Processes in DNA
ReplicationFigure 7.5a
6Initial Processes in DNA ReplicationDNA polymerase binds to
each strand and adds nucleotides to hydroxyl group at 3 end of
nucleic acidReplicates DNA only 5 to 3Because strands are
antiparallel, new strands synthesized differently7DNA
ErrorsReplication is not 100% accurateErrors occur when copying
DNADNA damagedUltraviolet lightX-raysCigarette smokeNitrates
(smoked meat)Pesticides & Herbicides8Effects of MutationFigure
7.21a-c
9Effects of MutationFigure 7.21d-e
10An English ExampleTHEBOYANDTHEDOGRANFAR
THE BOY AND THE DOG RAN FAR
Missense:THE BOY AND THE HOG RAN FAR
Nonsense:THE BOY AND .
11English Example-FrameshiftTHEBOYANDTHEDOGRANFAR
THE BOY AND THE DOG RAN FAR
DEletion:THE BOY ADT HED OGR ANF AR
Insertion:THE EBO YAN DTH EDO GRA NFA R
12MutagensRadiationIonizing radiation induces breaks in
chromosomesNonionizing radiation induces pyrimidine dimersChemical
mutagensNucleotide analogs disrupt DNA and RNA replication and
cause point mutationsNucleotide-altering chemicals result in
base-pair substitution mutations and missense mutationsFrameshift
mutagens result in nonsense mutations13DNA RepairFigure 7.25c-d
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