3.1: Protein targetting to organelles

Question 1

signal hypothesis

Answer 1

‘proteins have intrinsic signals that govern their transport and localization in the cell’

Question 2

what is the default destination for proteins and how many proteins remain here

Answer 2

cytosol
70%

Question 3

5 general steps for protein targetting

Answer 3

1. signal - targets protein
2. receptor - recognises signals
3. protein loosely folded/unfolded to cross membrane
4. tranlocation machinery to allow crossing of memb
5. energy via ATP or GTP

Question 4

is a signal sequence for proteins part of the mature protein?

Answer 4

no, usually cleaved off