RNA translation Flashcards
what are the two ends of a tRNA molecule?
anticodon
amino acid joined by an ester bond
what does RNA synthetase do?
joins amino acid onto tRNA
when is a tRNA charged and uncharged?
charged - amino acid attached
uncharged - no amino acid
what causes degeneracy?
3rd amino acid on the anticodon causes a wobble so it can be used for multiple codons
explain the initiation stage of translation
IF1 and IF3 separate the large and small subunit of the ribosome
small subunit binds to mRNA on the Shine-Dalgarno region
IF2 binds tRNA to mRNA
Large subunit joins and all IFs are released
what are the three sites on the ribosome and what do they do?
A site - aminoacyl-tRNA binding site
P site - peptidyl-tRNA binding site
E site - exit site
explain elongation in translation?
initiator tRNA at the P site
new charged tRNA binds at the A site next to it
peptide bond between amino acids
initiator tRNA is uncharged and moves to E site and leaves
tRNA with amino acid moves to P site, new tRNA comes to A site and process continues
explain termination is translation
at stop codon, a release factor cleaves the bond between the tRNA and the polypeptide so it can leave the ribosome
name some of the mechanisms of post-translational modification
phosphorylation glycoslyation lipidation cleavage of peptide bonds formation of disulphide bonds
what antibiotics target 30S ribosomes?
Tetracyclines
Aminoglycosides
what antibiotics target 50S ribosomes?
macrolides
lincosamides
chloramphenicol
