Translation

Question 1

What are the steps of prokaryotic elongation?

Answer 1

aminoacyl-tRNA binds A site
peptide bond forms
translocation

Question 2

What are 3 release factors to terminate prokaryotic elongation?

Answer 2

RF1, RF2 recognise and bind to stop codons

RF3-GTP proofreads, stimulates RF1 and 2 release

Question 3

What are the prokaryotic ribosome components?

Answer 3

23S, 5S -> 50S
16S -> 30S
50S -> 30S -> 70S

Question 4

What are the eukaryotic ribosome components?

Answer 4

28S, 5.8S, 5S ->60S
18S -> 40S
60S + 40S -> 80S

Question 5

How is eukaryotic translation initiated?

Answer 5

Only Met-tRNA can recognise first AUG

Question 6

What is the Kozak sequence?

Answer 6

Consensus sequence on eukaryotic mRNA involved in eukaryotic translation initiation
(5)’ ACCAUGG (3’)

Question 7

What is the elongation cycle in protein synthesis?

Answer 7

Entry of aa-tRNA at A site
EF1-alpha-GTP binds
GTP hydrolysis, ribosome conformational change
Peptide bond formation
Ribosome translocation, EF2-GTP–> EF2-GDP+Pi
Peptidyl tRNA cleavage

Question 8

To what is the polyA tail added?

Answer 8

mRNA