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18 Cards in this Set
- Front
- Back
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What are the diff. types of RNA
What is heaviest; of which is there the most; etc. |
mRNA - lightest - heterogenous.
tRNA - middle - middle amount rRNA - HEAVEIEST - most amount! |
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operon
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a cotranscribed gene on which there are several genes transcribed as one single RNA precursor.
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Coding/Template strands
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both are the strands of the duplex.
The template is complementary to RNA RNA is essentially the same as coding. |
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Composition of Bacterial RNA Polymerase
Core: Holoenzyme: |
Core - a2BB'
Holoenzyme - a2BB'sigma |
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significance of the Sigma factor in RNA polymerase
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required for recognition of the -10 region; binds to polymerase as it begins transcription.
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What does CAP stand for
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catabolite activator protein
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What is Cap's function
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controls DNA replicatoin! binds to site 60 bp's upstream ONLY when cAMP is bound to DNA. STabilizes it so RNA polymerase can bind at promotor.
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How does cAMP affect CAP and RNA polymerase?
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ALLOWS CAP TO RECOGNIZE SPCF SEQUENCE 60 BP UPSTREAM. when cAMP binds to CAP it changes the conformations of the two dimers of CAP so that their alpha helices bind to the major grooves of DNA.
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Role of mRNA
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messenger that encodes protein sequence information
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rRNA
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machinary for manufacturing the polypeptide chain
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function of tRNA
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adaptor molecule that allows the mRNA to be read
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what is the acceptor stem
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the 3' OH end of tRNA; covalently links to an Amino Acid's carboxyl terminus
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How many tRNA's are there for each amino acid?
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at least one!!!
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what is the secondary structure of tRNA
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a cloverleaf
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what is the tertiary structure of tRNA?
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an L
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UAA UAG and UGA
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nonsense codons
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nonsense codons
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UAA UGA UAG
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4 characteristics of the genetic code:
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-unambiguous (codon for 1 single AA)
-unpunctuated (only stop/start signals) -nonoverlapping (read triplets in sequence) -conservative (related AA encoded by related triplets) |
