Transcription And Translation Flashcards
What is the transcription promoter region?
TATAAA box
Which direction does RNA polymerase read its template strand?
3’ to 5’ (makes mRNA 5’ to 3’)
What are the three parts of mRNA processing?
5’ cap - a 5’-5’ link is made to a guanine nucleotide (role in protection and translation)
Poly A tail - polyadenylation of 3’ - protection from degradation
Splicing - removal of introns from DNA - makes mature mRNA
When does mRNA processing occur?
As mRNA is made (by RNA polymerase)
What enzyme adds the poly A tail and where?
Poly A polymerase.
Acts after a specific endonuclease recognises and cleaves at sequence AAUAA
What are the differences between prokaryotic and eukaryotic ribosomes?
Prokaryotic ribosomes - 50s + 30s = 70s
Eukaryotic ribosomes - 60s + 40s = 80s
What is the start codon? (Initiation of transcription)
AUG - methionine
What are the three stop codons? (Termination of translation)
UAA, UAG, UGA
What is the wobble position on tRNA?
The 5’ base of anticodon - where abnormal base pairing is possible
What is inosine?
A base used only in tRNA that recognises/base pairs with more than one codon a recognises U, A or C
What is the function of aminoacyl-tRNA synthetase?
Activate amino acids (using ATP, releasing AMP) and adding these to tRNA producing an aminoacyl-tRNA
What’s the function of peptidyl transferase?
Forms peptide bonds moving amino acid sequences from P site into A site. (Uncharged tRNA released)
Why don’t RNA polymerases have proofreading capability?
An error in mRNA causes an error in a single protein - which will probably be degraded (therefore temporary) .
Also lots of other copies of that mRNA and protein therefore minimal effect of cell
