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Gel electrophoresis
DNA sequencing
Cytoplasm
Nucleus
DNA
DNA is the genetic material within the nucleus.
Central Dogma
RNA
Protein
Replication
The process of replication creates new copies of DNA.
TranscriptionThe process of transcription
creates an RNA using
DNA information.
TranslationThe process of translation
creates a protein using
RNA information.
DNA Double Helix-Held Together with
H-Bonds
Base Pairs Double Helix
base: thymine(pyrimidine)
sugar: 2’-deoxyribose
monophosphate
no 2’-hydroxyl
(5’ to 3’)
5’
3’
base:adenine(purine)
1’2’
4’
3’ linkage
5’ linkage
Three Components of DNA Structure
Pyrimidines used in Base Pairs, DNA
6-membered rings only
Purines used in Base Pairs, DNA
Fused 5 and 6 member rings
DNA Base Pairing
A-T pairing
2 H-Bonds
G-C pairing
3 H-bonds
A-T and G-C Base Pairs Hold the DNA helices together
A-T and G-C Base Pairs Hold the DNA helices together
A-T and G-C Base Pairs Hold the DNA helices together
A-T and G-C Base Pairs Hold the DNA helices together
A-T and G-C Base Pairs Hold the DNA helices together
Transcription• The new RNA molecule is formed by incorporating • nucleotides that are complementary to the
template strand.
DNA coding strand
DNA template strand
DNA
5’
3’
5’
3’
G T C A T T C G G
C A G T A A G C C
G
RNA
5’
GG U C A U U C
3’
# of strands
kind of sugar
bases used
RNA Polymerase is the Enzyme that Catalyzes Transcription of DNA Information to RNA
DNA (Blue)
Newly Synthesized RNA (Red)
Active Site Metal (Pink)
Bridge Helix Moves DNA through Polymerase during RNA Synthesis (Green)
Transcription• The new RNA molecule is formed by incorporating • nucleotides that are complementary to the
template strand.
DNA coding strand
DNA template strand
DNA
5’
3’
5’
3’
G T C A T T C G G
C A G T A A G C C
G
RNA
5’
GG U C A U U C
3’
Translation• The process of reading the RNA sequence of an
mRNA and creating the amino acid sequence of a protein is called translation.
Transcription
Codon Codon Codon
Translation
DNA
T T C A G T C A G
DNAtemplatestrand
mRNA
A A G U C A G U C MessengerRNA
Protein Lysine Serine ValinePolypeptide(amino acidsequence)
• The “words” of the DNA “language” are triplets of bases called codons
– 3 bases or nucleotides make one codon
– Each codon specifies an amino acid
– The codons in a gene specify the amino acid sequence of a polypeptide
Genetic information written in codons is translated into amino acid sequences
• Virtually all organisms share the same genetic code
• All organisms use the same 20 aa
• Each codon specifies a particular aa
The genetic code is the Rosetta stone of life
Figure 10.8A
• Tryptophan and Methionine have only 1 codon each
• All the rest have more than one
• AUG has a dual function
• 3 stop codons that code for termination of protein synthesis
• Redundancy in the code but no ambiguity
Figure 10.8A
http://www.dnalc.org/ddnalc/resources/sangerseq.html
http://www.shsu.edu/~chm_tgc/sounds/flashfiles/GE.swf
Shotgun sequencing: assembly of random sequence fragments