Question

Which path represents vesicle transport in the retrograde (reverse) direction? Select one: a. Golgi to Plasma membrane o b. Golgi to ER c. Golgi to Lysosome d. Golgi to Secretory vesicle e. Golgi to Endosome 0 The translocon orients the first transmem-brane domain so that the positive (+) flanking charge faces the_ and the negative (-) flanking charge faces the Select one: a. ER lumen; ER lumen b. cytoplasm; cytoplasm c. The transmembrane domain is oriented randomly d. cytoplasm; ER lumen e. ER lumen; cytoplasm

Answer 1

1.Ans is b golgi to ER.

Reason : direction of secretary pathway is :

Free ribosome - ER - Golgi -secretary vesicle - plasma membrane/lysosome - integral or peripheral membrane protein/ secreted out in extracellular matrix.

Hence golgi to ER is reverse process and is important to resend the ER proteins.

2. Ans is (E) +vely flanking charge means -N terminal will face the ER lumen while -vely charged or -C terminal will face the cytoplasm.

Note: This is the general case .It is also possible that -C terminal face Er lumen and -N terminal face cytoplasm but that is not a random process and depends upon the presence of type of signal sequence either internal or external.