Lecture 11 Flashcards
What are the three steps of transcription?
Initiation- read promotor
Elongation
Termination
How does transcription initiation work?
Only genes are transcribed.
Promoter known as a Tataaaa box recruits RNA polymerase. Downstream refers to direction mRNA is made in. Transcription start site is at the end of polymerase and so a bit down from the Tataaaa box.
Upstream sequences and mutations in promoter Tataaaa can affect transcription
What does elongation involve?
Creating mRNA from template strand and so as seem information as coding strand.
What are the three processes involved in turning pre-mRNA into mature mRNA?
Capping
At 5 prime end
Tailing or polyadenylation
Poly A tail- length determines stability
Splicing- remove introns
What is the clinical relevance of prokaryotes and eukaryotes having different ribosome types?
Antibiotics can target prokaryotic ribosomes and inhibit transcription without affecting eukaryotic ones.
What are the start and stop codons?
Start- AUG
Stop- UAA UAG UGA
What are the three steps of translation?
Initiation
Elongation
Termination
TRNA codon recognition?
Inosine is a base that can bind to U C or A and allows tRNA to bind to different codes.
What is the wobble position?
The 5’ base of anticodon and 3’ base of codon makes the wobble position. This is a place where a single tRNA species. Can recognise more than one codon ( due to inosine)
How are tRNA for translation produced?
En enzyme used ATP to join an amino acid to a tRNA molecule
How is translation initiated?
CAP recognised by specific tRNA and recruits half ribosome. Ribosome moves along until start codon AUG found. Then other half of ribosome (60S subunit) recruited for translation .
How does elongation in translation happen
Methionine is the first amino acid at start codon. Next codon recognised by tRNA with amino acid bound. Ribosome moves on and leaves free site for next tRNA. Peptide bonds formed through peptide transferase.
