Class 11 - Intracellular Vesicular Traffic (GOOD)

Question 1

Endocytic pathway

Answer 1

Endocytosis - Import of materials.

Question 2

Secretory pathway

Answer 2

Exporting of materials. Often involves exocytosis.

Macromolecules modified and either used in cell or stored/exported out.

Question 3

Transport vesicles

Answer 3

Single membrane bound vesicles used for transport between compartments and to plasma membrane.

Question 4

Coated vesicle and 2 functions

Answer 4

Transport vesicle with protein structure surrounding it. Coat dissociates before vesicle fuses with target membrane.

1. Allows for selection of correct cargo type.
2. Helps form vesicle, bending it into sphere.

Question 5

Clathrin

Answer 5

“Soccer balls” which form clathrin coat.

Question 6

Cargo receptor

Answer 6

Bind to cargo and adaptor proteins for clathrin-coated vesicles

Question 7

Adaptor proteins

Answer 7

Bind clathrin to membrane and trap cargo receptors.

Question 8

Dynamin

Answer 8

A GTPase involved in formation of clathrin-coated vesicles. Trims neck of vesicle when it’s being pinched off from donor membrane.

Question 9

GTPases

Answer 9

Function as on/off switches for various cell functions, including vesicle coat assembly and disassembly.

Include ARF (Golgi) and Sar1 (ER)

Question 10

Sar1

Answer 10

A GTPase involved in COPII coat assembly at ER.

(Sar1-GEF, Sar1-GDP)

Question 11

Rab proteins

Answer 11

GTPases which direct vesicles to specific locations on target membrane.

Question 12

Rab effector

Answer 12

Rab-GTP binds to this on target membrane, tethering the vesicle to the membrane.

Question 13

SNAREs

Answer 13

Mediate membrane fusion. Exist in complementary pairs: v-snares (transport vesicles) and t-snares (target membrane).

Wrap around each other, water squeezed out, membranes fuse.

Question 14

Hemifusion

Answer 14

Half-fusion. When membrane vesicle and target compartment are half fused together.

Question 15

Three types of coated vesicles

Answer 15

1. Clathrin coated
   Plasma membrane—>Early endosome
   Golgi—> Late endosome
   Retrieval pathway back to Golgi
2. COPI
   Retrieval pathways
3. COPII
   ER—>Golgi