Lecture 11

Question 1

What is the transport of the folded ER protein to the golgi mediated by?

Answer 1

transport vesicles that bud from the ER and fuse with the golgi

Question 2

What forms membrane vesicles?

Answer 2

Formed by coat proteins

Question 3

Where do COP proteins form the vesicle at?

Answer 3

At the ER and the Golgi

Question 4

What are the two steps of vesicle formation?

Answer 4

• soluble ER proteins are sorted into forming vesicles by cargo receptors
• transmembrane proteins are sorted into vesicles by binding to coat proteins

Question 5

How are vesicles fused with the golgi?

Answer 5

The ER derived vesicles uncoat, tether with the golgi, dock and fuse with the golgi

Question 6

What are Rab proteins?

Answer 6

Small GTPases that act as regulators/switches

Question 7

What acts as molecular switches?

Answer 7

small GTPases

Question 8

What do Rab GTPases regulate?

Answer 8

regulation of membrane fusion

Question 9

What do Sar 1 GTPases regulate?

Answer 9

ER vesicle formations

Question 10

What is GEF?

Answer 10

Guanine nucleotide exchange factor

Question 11

What is GAP

Answer 11

GTPase accelerating proteins

Question 12

What do small GTPases NOT do?

Answer 12

• don’t hydrolyze GTP spontaneously
• Don’t exchange GDP with GTP without help (requires GAP and GEF)

Question 13

What is V-SNARE connected to?

Answer 13

transport vesicle

Question 14

What is T-SNARE connected to?

Answer 14

target membrane

Question 15

What process drives membrane fusion?

Answer 15

docking

Question 16

What are the functions of the golgi aparatus?

Answer 16

protein sorting

Question 17

Where are proteins sent?

Answer 17

Other proteins are sent to the cell surface or endosomal system
Proteins that are supposed to remain in the ER are sent back to the ER

Question 18

What is the role of the CIS side of the golgi?

Answer 18

Receives vesicles from the ER

Question 19

What is the job of the trans side of the golgi?

Answer 19

Form transport vesicles that traffic to endosomes or the cell surface

Question 20

What is the role of constructive secretion?

Answer 20

delivery of plasma membrane proteins

Question 21

What is the role of regulation secretion?

Answer 21

secretion of regulatory proteins

Question 22

Describe the regulated secretion of insulin … As glucose is increased, the ATP levels are increased which close ….

Answer 22

K+ channels, which causes depolarization of membrane potential, which opens Ca2+ channels, which triggor fusion of insuling - containing vesicles with the plasma membrane

Question 23

What triggers a rapid fusion of vesicles with the plasma membrane?

Answer 23

Increase in calcium levels caused by an action potential

Question 24

When are synaptic vesicles ready to fuse?

Answer 24

After docked and primed

Question 25

What is the contact site between cell interior and exterior?

Answer 25

Plasma membrane

Question 26

What functions are localized to the cell surface?

Answer 26

transport function and signaling

Question 27

What happens in the absence of uracil?

Answer 27

Fur 4 localizes to the eisosomes

Question 28

What are eisosomes?

Answer 28

long membrane furrows

Question 29

What keeps the nutrient transporter in the inactive state?

Answer 29

gel like membrane of the eisosome

Question 30

What does the fluidlike membrane allow for in the eisosome?

Answer 30

allows transporter to efficiently import nutrients

Question 31

What happens during endocytosis?

Answer 31

- uptake of nutrients - degradation of cell surface proteins/lipids - cell signaling/communicating - immune response

Question 32

What happens during phagocytosis?

Answer 32

- engulfing large particles - the membrane raps around the particle

Question 33

What happens during pinocytosis?

Answer 33

- uptake of fluid filled vesicles formed by clathrin

Question 34

What is clathrin?

Answer 34

Made of 2 types of proteins which assembles into a cage that deforms the membrane

Question 35

What is clathrin mediated by?

Answer 35

endocytosis

Question 36

Clathrin and adaptors function in what?

Answer 36

cargo selection

Question 37

What does Low density lipoprotein (LDL) do?

Answer 37

Delivers cholesterol and fat to cells

Question 38

Triacylglycerol and chlesterylester are what?

Answer 38

storage fats

Question 39

Where does the LDL receptor shuttle?

Answer 39

Between cell surface, endosome and back to the cell surface

Question 40

What are endosomes?

Answer 40

Are protein and lipid storing compartments of the endocytic system

Question 41

What are early endosomes?

Answer 41

Receive endocytic vesicles and recyle part of the material back to the cell surface

Question 42

What is the role of lysosome/vacuoles?

Answer 42

a storage compartment for salts and amino acids acidic compartment with enzymes to degrade macromolecules

Question 42

What are late endosomes (MVB)?

Answer 42

package membrane and proteins into the lumen of the compartment and deliver their content to the lysosome for degradation