Translation Flashcards
What is a charged tRNA
Has Amino Acid on it
What is the A, P and E sites on tRNA?
Aminoacyl site accepts the amino acid. Peptodyl site is where new peptode bond forms (linking chain of AA). Exit site is where the trna gets kicked to and off back into the cytoplasm and is no longer charged
What is the first amino acid
fMet
what is the first codon
AUG
What sequence binds to 16S so aug is in the p site?
shine dalgarno
In initiation, the 30s first finds to what two things?
IF 1 and IF 3
what joins the tRNA and fMet on the 30S small subunit in initiation?
GTP bound IF-2
For termination of translation, what are the 3 UNIVERSAL stop codons?
UAA, UAG, UGA
What happens during the termination of translation?
Ribosome stalls when it reaches the nonsense/stop codon in the A site. The release factor binds to the A site and the polypeptide chain gets released and the ribosomes disassociate
What are some reasons that ribosomes stall randomly?
Prematurely stall due to coming across rare codons (some species are more used to certain codons)
Describe how tmRNA helps with stalling ribosomes
tmRNA is both transfer and messenger. it enters the A site and the ribosome translates its coding sequence instead of the one in mRNA that it stalled at. A short polypeptide tag is added to the C term of the nascent polypeptide and the ribosome and mRNA is released . This is called trans-translation
What is the p factor/ Rho?
a protein that is involved in the termination of transcription. It is a helicase that works when RNA is not being transcribed. If there are no ribosomes on the mRNA, Rho binds to rut when RNA pol reaches a pause site. It basically removed the newly transcribed mRNA from the pol
how does rho know when to bind and start the termination process
recognizes the rut site on the mRNA
