Chapter #10 10.1 Discovery of DNA 10.2 DNA Structure 10.3 DNA Replication 10.4 Protein Synthesis.
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Transcript of Chapter #10 10.1 Discovery of DNA 10.2 DNA Structure 10.3 DNA Replication 10.4 Protein Synthesis.
Chapter #10Chapter #10
10.1 Discovery of DNA10.1 Discovery of DNA10.2 DNA Structure10.2 DNA Structure10.3 DNA Replication10.3 DNA Replication10.4 Protein Synthesis10.4 Protein Synthesis
Griffith’s ExperimentsGriffith’s Experiments
Griffith’s Experiments (2)Griffith’s Experiments (2)
19281928 A mouse injected w/ both heat killed S A mouse injected w/ both heat killed S
(virulent) and R types can cause (virulent) and R types can cause pneumoniapneumonia A HEREDITARY FACTOR must be released A HEREDITARY FACTOR must be released
and taken into the R typeand taken into the R type Is this factor protein? DNA? RNA?Is this factor protein? DNA? RNA?
Avery’s ExperimentsAvery’s Experiments 1940’s1940’s Wanted to determine if the material that was Wanted to determine if the material that was
transforming was protein, DNA or RNAtransforming was protein, DNA or RNA Protease to destroy proteinProtease to destroy protein
Injected w/heat killed S cells and R cellsInjected w/heat killed S cells and R cells Able to transform R to SAble to transform R to S
RNase to destroy RNARNase to destroy RNA Injected w/heat killed S cells and R cellsInjected w/heat killed S cells and R cells Able to transform R to SAble to transform R to S
DNase to destroy DNADNase to destroy DNA Injected w/heat killed S cells and R cellsInjected w/heat killed S cells and R cells Not able to transform R to SNot able to transform R to S
Hershey-ChaseHershey-Chase Experiment Experiment
19521952 Protein or DNA?Protein or DNA?
Little protein found Little protein found
in viruses; all the in viruses; all the
DNA was presentDNA was present
DNA!!!!!DNA!!!!!
The Structure of DNAThe Structure of DNA
Sugar-Phosphate BackboneSugar-Phosphate Backbone Deoxyribose (sugar found in DNA)Deoxyribose (sugar found in DNA)
Nitrogen BasesNitrogen Bases AdenineAdenine ThymineThymine GuanineGuanine CytosineCytosine
The Structure of DNA (2)The Structure of DNA (2)
PurinePurine Double ringed baseDouble ringed base Guanine and ThymineGuanine and Thymine
PyrimidinePyrimidine Single ringed baseSingle ringed base Cytosine and AdenineCytosine and Adenine
Purines must pair with pyrimidines so the Purines must pair with pyrimidines so the helix can be made (it can twist)helix can be made (it can twist)
DNA DNA
Deoxyribonucleic acidDeoxyribonucleic acid
Contains genes that code for proteinsContains genes that code for proteins
Involved in heredityInvolved in heredity
AdenineAdenine
Nitrogen base in both DNA and Nitrogen base in both DNA and RNARNA
Purine that pairs with thymine in Purine that pairs with thymine in DNA and uracil in RNADNA and uracil in RNA
GuanineGuanine
Nitrogen base in both DNA and Nitrogen base in both DNA and RNARNA
Purine that pairs with cytosine in Purine that pairs with cytosine in both DNA and RNAboth DNA and RNA
ThymineThymine
Nitrogen base in DNA onlyNitrogen base in DNA only Pyrimidine that pairs with adeninePyrimidine that pairs with adenine
CytosineCytosine
Nitrogen base found in both DNA Nitrogen base found in both DNA and RNAand RNA
DeoxyriboseDeoxyribose
5 carbon sugar found in DNA5 carbon sugar found in DNA
Makes up the backbone of DNA Makes up the backbone of DNA (sides of the ladder)(sides of the ladder)
Phosphate GroupPhosphate Group
Backbone of DNABackbone of DNA Alternates with deoxyriboseAlternates with deoxyribose
Hydrogen BondsHydrogen Bonds
Bond that joins the nitrogen bases Bond that joins the nitrogen bases togethertogether
NucleotideNucleotide
Building block of nucleic acidsBuilding block of nucleic acids Contains…Contains…
5 carbon sugar5 carbon sugarNitrogen baseNitrogen basePhosphate groupPhosphate group
DNA Carries the Genetic CodeDNA Carries the Genetic Code
ReplicationReplication
Process of duplicating DNA Process of duplicating DNA Results in 2 DNA molecules (old Results in 2 DNA molecules (old
and new strands mixed)and new strands mixed) Replication is said to be semi-Replication is said to be semi-
conservativeconservative
DNA HelicaseDNA Helicase
Enzyme responsible for the untwisting of Enzyme responsible for the untwisting of DNADNA
Starts the replication processStarts the replication process
DNA PolymeraseDNA Polymerase
Enzyme responsible for attaching the Enzyme responsible for attaching the nucleotides in the correct order during nucleotides in the correct order during replication.replication.
DNA RNADNA RNA
DeoxyriboseDeoxyribose Double strandedDouble stranded ThymineThymine One versionOne version
RiboseRibose Single strandedSingle stranded UracilUracil 3 versions3 versions
Sugar-Phosphate backboneNucleic Acids Adenine, Guanine, Cytosine
Steps in replicationSteps in replication
DNA helicase unwinds the DNA molecule at DNA helicase unwinds the DNA molecule at several spotsseveral spots Breaks the hydrogen bonds between the basesBreaks the hydrogen bonds between the bases
DNA polymerase adds new nucleotidesDNA polymerase adds new nucleotides 2 new strands2 new strands
Original strand + new strand = semiconservative Original strand + new strand = semiconservative modelmodel
Structure of RNAStructure of RNA
Uracil – nitrogen base found only in Uracil – nitrogen base found only in RNA (pyrimidine)RNA (pyrimidine)
Ribose – 5 carbon sugar found only in Ribose – 5 carbon sugar found only in RNARNA
Types of RNATypes of RNA
tRNA - transfertRNA - transfer mRNA - messengermRNA - messenger rRNA - ribosomalrRNA - ribosomal
tRNAtRNA
Used to carry amino acids to codons on Used to carry amino acids to codons on mRNAmRNA
Contains the anticodons on one end and Contains the anticodons on one end and an amino acid on the other endan amino acid on the other end
mRNAmRNA
Contain codonsContain codons Made through transcription in the Made through transcription in the
nucleusnucleus Read by the tRNA during translation in Read by the tRNA during translation in
the ctyoplasmthe ctyoplasm
Transcription Vs. TranslationTranscription Vs. Translation
Transcription – process of making RNA Transcription – process of making RNA from DNA in the nucleus of the cellfrom DNA in the nucleus of the cell
Translation – process of making proteins Translation – process of making proteins tRNA recognizes codons of the mRNA and tRNA recognizes codons of the mRNA and
attaches the amino acids in the correct attaches the amino acids in the correct sequence for the protein that DNA coded sequence for the protein that DNA coded for. for.
CodonCodon
Set of 3 bases found on mRNASet of 3 bases found on mRNA Complementary to the anticodon on the Complementary to the anticodon on the
tRNAtRNA
AnticodonAnticodon
Set of 3 bases found on a tRNA Set of 3 bases found on a tRNA moleculemolecule
Recognizes the codon on mRNA during Recognizes the codon on mRNA during translationtranslation
Amino AcidAmino Acid
Building block of a proteinBuilding block of a protein 20 different kinds (essential and 20 different kinds (essential and
nonessential)nonessential)
Peptide BondPeptide Bond
Bond that joins amino acids together in Bond that joins amino acids together in the growing polypeptide chainthe growing polypeptide chain
PolypeptidePolypeptide
Made through translationMade through translation Growing chain of amino acids that Growing chain of amino acids that
transforms into a proteintransforms into a protein
RNA PolymeraseRNA Polymerase
Enzyme responsible for attaching RNA Enzyme responsible for attaching RNA nucleotides in the correct order. nucleotides in the correct order.
Steps of Transcription (in Steps of Transcription (in the nucleus)the nucleus)
DNA is the templateDNA is the template
RNA polymerase adds the RNA nucleotidesRNA polymerase adds the RNA nucleotides Uracil replaces ThymineUracil replaces Thymine
Once transcribed, mRNA leaves the nucleus and Once transcribed, mRNA leaves the nucleus and enters the cytoplasmenters the cytoplasm
Hooks up with a ribosome to begin translationHooks up with a ribosome to begin translation
Steps of TranslationSteps of Translation
Ribosome, mRNA and tRNA needed to beginRibosome, mRNA and tRNA needed to begin
Anticodon on tRNA matches with the codon on Anticodon on tRNA matches with the codon on mRNAmRNA Always begins w/ start codon (AUG)Always begins w/ start codon (AUG)
Adjacent amino acids form peptide bondsAdjacent amino acids form peptide bonds
tRNA keeps adding amino acids until the stop tRNA keeps adding amino acids until the stop codon is readcodon is read
Steps of TranslationSteps of Translation
tRNA releases the polypeptide chain (it tRNA releases the polypeptide chain (it will fold and become a functional will fold and become a functional protein)protein)
““naked” tRNA molecules find more naked” tRNA molecules find more amino acids and the process starts all amino acids and the process starts all over (as certain proteins are needed)over (as certain proteins are needed)