HTHSCI 1LL3 Lecture Notes - Lecture 10: Germ Cell, Ribosomal Rna, Guanine
TRANSCRIPTION
DĀ§Ā¢D D
Primary Transcript
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Transcription :RNA synthesis 1mm aDNA template
-
uses apolymerase that jaw nucleotides to form asingle strand
-
Difference between the sequence in the DNA coding strand is that Utakes places of TmRNA
RNA Polymerase
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Polynucleotide strand is synthesized similar to DNA ,in the 5' ā 3 'direction Icopied tom the template strand in the 3' ā s 'direction )
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RNA polymerase is able to initiate synthesis without a primer and lacks a separate proofreading exo nuclease
(coding)āmessage in
RNAIDNA Relationship correct
(template)order
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language of DNA āRNA āProtein
to builds RNA
ā¢3nucleotides code for 1amino acid ātakes message
/from DNA Into
cytosol to make
Starting
Cod On Protein
RNA Polymerases
ā¢Bacteria have one RNA polymerase that transcribes all the different types of RNA in the cell
ā¢
Eukaryotes have an individual RNA polymerase for each of ā RNA ,mRNA and tRNA
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RNA polymerase Iā
produces VRNA Inever transcribed )
Coding Region
-RNA
polymerase 11 āproduces mRNA 5'
31
-
RNA polymerase 111 āproduces tRNA Inever transcribed )
ā¢
An
RNA polymerase must be able to recognize the start point and the correct strand to transcribe
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Promoter :site of attachment for the RNA polymerases and identities the start point for transcription (expression of the gene :transcript to pnhm)
Anatomy of a Eukayohc Gene
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The gene is made up of a promoter and transcribed region
ā¢The genetic sequence is numbered from Hfor the start site
ā¢The "
upstream "
or s'
-flanking region is numbered negatively from +1 latter transcription)
-
TATA box Dhere
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Eukaryote genes contain huh coding regions called htrons that must be removed ;RNA must 9110 be modified before transport
Promoters
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promoters :binding slkslvr Polymerases (upstream)
-
Consist of an AT rich region in prokaryotes +eukayoks and are
"
a's
"
-acting since they are located on the same molecule
-
trans -actna :proteins that bind and enhance or prevent transcription
Opewns
ā¢Ideft asingle promoter in bacterial cells that
controls
anumber of genet
-
produces pdyuslnnk transcript that is translated to several proteins Kcodes for proteins
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e9 .lacopevon allows e. coli to metabolize lactose for food source