tRNAs

Question 1

two types of Aminoacyl-tRNA synthetases

Answer 1

class 1: adds OH to the 2’ end which will be switched out for 3’; class 2: adds to the 3’ oH

Question 2

aatS are quite selective–only 1/10 000 or 1/100 000 tRNAs will have the wrong amino acid

Answer 2

ya

Question 3

how does the aa-tRNA synthetase check for fidelity?

Answer 3

through the editing site–if the right amino acid was put on it won’t fit into editing site; the wrong one, smaller, was put on, it’ll fit–> be hydrolysed off

Question 4

translation initiation

Answer 4

30S subunit (16S rRNA) binds and then scans the mRNA for a shine-dalgarno seq (AGGAGG); initiation occurs at an AUG 4-8 bases later;

Question 5

what is discharging of a tRNA, and what it is determined by?

Answer 5

placement during elongation; determined by the anticodon loop binding to mRNA

Question 6

what is charging of a tRNA, and what is it determined by?

Answer 6

replacement of aa, determined by acceptor stem as one aaRS charges multiple tRNAs for one aa