Dna y expresión genética
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Bio111 2009 DNA y Expresión Genética
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Transcript of Dna y expresión genética
Bio1112009
DNA y Expresión Genética
DNAMolécula con información genética
Dirige la síntesis de cadena polipéptida
Autoreplicable
Estructura del DNANucleótidos
Bases nitrogenadas purinas piridiminasPentosa- desoxiribosaGrupo fosfato
Thymine
AdenineNucleotide
Cytosine
Guanine
Deoxyribose(sugar)
Phosphodiesterlinkage
Phosphategroup
(a) Adenine Thymine
Deoxyribose Deoxyribose
DeoxyriboseDeoxyribose
Guanine Cytosine
2.0 nm
Majorgroove
Minorgroove
3.4nm
Sugar-phosphatebackbone
0.34 nm
= hydrogen
= atoms in base pairs
= phosphorus
= oxygen
= carbon
Replicación semiconservativa
Figure 11-10Page 228
DNA polymerase
DNA polymerase Origin of replication
Single-strandedbinding proteins
Direction ofreplicationRNA primer
DNAhelicase
Twist introduced intothe helix by unwinding
3’5’
3’5’
3’5’
3’5’
3’5’
3’5’
3’5’
3’5’
3’3’
3’
Leading strand
RNA primer
DNA polymeraseReplication fork
Lagging strand(first Okazaki fragment) Direction of
replication
DNA helix
5’
3’5’
3’5’
3’5’
Leading strand
DNA ligase Third Okazaki fragment
Direction ofreplication
3’
5’
3’5’
3’5’
3’5’
3’ 5’
Lagging strand
Leading strand
DNA ligase Third Okazaki fragment
Direction ofreplication
3’
5’
3’5’
3’5’
3’5’
3’ 5’
Lagging strand
Transcripción
Traducción
Translation
Codon 1 Codon 2 Codon 3Codon 4 Codon 5Codon 6
Polypeptide
Nontemplate strand
TranscriptionDNA
Template strand
mRNA(complementarycopy of templateDNA strand)
Second letter
U C A GF
irst
lett
er (
5’ e
nd)
U
C
A
G
Thi
rd le
tter
(3’
end
)
UCAG
UCAG
UCAG
UCAG
= Stop Codon
= Start Codon
Promoter region Transcribed region
mRNA terminationsequence
Upstreamleadersequences
Protein-coding sequencesTranslated region
Downstreamtrail ingsequences
Start codon Stop codon – OH3’ end
Polypeptide
5’
3’5’
3’
5’ end
mRNA
Leadersequence
mRNA
Smallribosomalsubunit
Start codon
Init iat ion factor
5’ 3’
fMet
InitiatortRNA
3’ 5’
5’ 3’
fMetP site
E site
Init iation complex
A site
Largeribosomalsubunit
5’ 3’
Promoter
TemplateDNA strand
7-methylguanosine cap
1stexon
1stintron
2ndexon
2ndintron
3rdexon
mRNA terminationsequence
Transcription , capping of 5’ end
Stop codonStart codon
5’ end
(continue to next sl ide)
(continue to next sl ide)
–AAA...Poly-A tail3’ end
5' end
1stexon
2ndexon
3rdexon
Protein-coding region
Nuclear pore
Transport through nuclearenvelope to cytosol
Nuclear envelope
Cytosol
5' endLeader Start codon Stop codon
–AAA...Poly-A tai l3' end
