Protein Translation and Post-Translational Modifications

Question 1

What is the translation speed?

Answer 1

15 A.A per second

Question 2

What does polyribosome mean?

Answer 2

multiple ribosomes work on a single mRNA

Question 3

How do antibiotics work on protein synthesis?

Answer 3

disrupt the mechanism by exploiting differences between bacterial and eukaryotic mechanisms

Question 4

Give examples of antibiotics and what they inhibit

Answer 4

streptomycin - initiation
tetracycline- aa-tRNA binding
erythromycin - translocation
chloramphenicol - peptide transferase
puromycin - terminates elongation

Question 5

What proteins are synthesised oon RER?

Answer 5

secretory or transmembrane

Question 6

What are the first 20-24 A.A of RER mRNA?

Answer 6

signal sequence

Question 7

Summarise RER translation

Answer 7

protein-RNA complex/signal recognition particle recognises signal sequence and halts translation, SRP binds to receptor on RER surface and translation resumes with translocation of peptide into ER lumen

Question 8

What happens to the signal sequence at the end of translation?

Answer 8

cleavage by signal peptidases

Question 9

Purpose of post-translation modification

Answer 9

increase diversity

Question 10

Post-Translational modification examples

Answer 10

glycosylsation, phosphorylation, acylation/prenylation (+ lipid), hydroxylation (+ collagen), proteolytic cleavage