PROTEIN SYNTHESIS TRANSCRIPTION: DNA m RNA TRANSLATION: m RNA Protein.
Transcription - Ms. kropac€¦ · RNA Protein Transcription Translation Tuesday, November 14, 17....
Transcript of Transcription - Ms. kropac€¦ · RNA Protein Transcription Translation Tuesday, November 14, 17....
Transcription
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OverviewDNA
RNA
Protein
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OverviewDNA
RNA
Protein
Transcription
Translation
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Don’t Write This Down . . .
If the cell wants to make a specific protein it will take a ‘photocopy’ of the section of DNA that carries the information for specific protein
This photocopy is known a RNA
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DNA RNA
deoxyribose, phosphate, nucleotide base
ribose, phosphate, nucteotide base
G, C, A, T G, C, A, U (Uracil)
double stranded single stranded
stable unstable
in the nucleus everywhere
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Tuesday, November 14, 17
Types of RNA
mRNA: Messenger RNA (transcription)tRNA: Transfer RNA (translation)rRNA: Ribosomal RNA (translation)
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Stages of Transcription
1) Initiation2) Elongation3) Termination
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Initiation
OverviewRNA polymerase binds to a promoter region
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Initiation
A promoter is a DNA sequence that is high in adenine and thymine (TATA box)It is adjacent to the gene to be transcribed
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Initiation
A promoter acts as a recognition/binding site for the TATA binding protein.
This protein is recognized by RNA polymerase II which docks to DNA
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Initiation
RNA polymerase unwinds the DNA and the template strand is exposed.
Only on strand of the DNA is transcribedThe promoter is NOT transcribed
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Tuesday, November 14, 17
Elongation
RNA polymerase binds with the promoter and builds in a 5’ → 3’ direction
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Elongation
No Okasaki fragments are created because only one strand is transcribed (no lagging strand)
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Elongation
RNA polymerase works faster than DNA polymerase because there is no proof reading.
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Elongation
Uracil complements adenine
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Tuesday, November 14, 17
Termination
A stop codon signals RNA polymerase to end transcription
UAA, UAG, UGA
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Termination
mRNA and RNA polymerase are releasedDNA that was being transcribed rewinds into double-helical form
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Tuesday, November 14, 17