Golgi

Question 1

What is the role of ER Exit Sites in vesicular transport?

Answer 1

They form transport vesicles and properly package them for transport to the Golgi

Question 2

What gives vesicles their unique ‘fuzzy’ surface appearance?

Answer 2

COP attached to the outside surface of the vesicle membrane.

Question 3

Name the three classes of vesicle coat proteins.

Answer 3

COPI, COPII and Clathrin

Question 4

In what direction does COPI travel?

Answer 4

Backwards from the Golgi to the ER, and backwards within the Golgi as well

Question 5

Vesicles that transport proteins from the Golgi and PM to endosomes are called;

Answer 5

Clathrin-coated vesicles

Question 6

Explain the function of Sar1-GDP.

Answer 6

It changes into Sar1-GTP to integrate into the ERES to create the bud that becomes a vesicle.

Question 7

True or False: ERES-derived vesicles traffic to the trans Golgi network.

Answer 7

False. They go to the cis Golgi network, which is closest to the ER.

Question 8

What mediates the movement of vesicles through the cytosol?

Answer 8

Cytoskeleton highways, and molecular motors that move them across the highways.

Question 9

What is the function of Rab proteins?

Answer 9

They recognize incoming vesicle and recipient membranes

Question 10

What is the name of the protein that forms a ‘bridge’ between vesicles and recipient membranes?

Answer 10

Tethering proteins

Question 11

The docking of vesicles is mediated by which proteins?

Answer 11

SNAREs

Question 12

True or False: SNAREs are located on every transport vesicle and recipient membrane.

Answer 12

True. They are necessary for proper docking

Question 13

What is the difference between t-SNAREs and v-SNAREs?

Answer 13

v-SNAREs and found on vesicles, and t-SNAREs are found on acceptor membranes.

Question 14

What type of sequence is responsible for escaped protein ER retrieval?

Answer 14

C-terminal KDEL sequence

Question 15

True or False: COPI recognizes the KKxx sequence on escaped ER membrane proteins.

Answer 15

True. This is how it is transported back to the ER from the Golgi.

Question 16

True or False: plant and animal cells have one large Golgi complex.

Answer 16

False. Plant cells often contain numerous Golgi complexes.

Question 17

How are the different Golgi sub compartments held together?

Answer 17

With GRASP tethering proteins

Question 18

What are Golgins?

Answer 18

Long, filamentous proteins that tether the Golgi to the cytoskeleton

Question 19

What is the name of the protein that facilitates ER to Golgi communication through microtubules?

Answer 19

GMAPs

Question 20

What is the function of the cis Golgi Network?

Answer 20

To receive transport vesicles from the ER and sort materials for transport.

Question 21

Name the three main sections of the Golgi cisternae.

Answer 21

The cis, medial and trans cisternae

Question 22

Which part of the Golgi mediates Golgi metabolism?

Answer 22

The cisternae

Question 23

What two types of protein coatings will transport vesicles that come from the trans Golgi network have?

Answer 23

Clathrin if the vesicle is going to the endosome or PM, or COPI if it’s going back to the cisternae

Question 24

Which organelle is known as the ‘processing plant’ of the cell?

Answer 24

The Golgi Complex

Question 25

True or False: N-linked glycosylation only occurs in the RER

Answer 25

False. N-linked glycosylation is started in the RER, but completed in the Golgi complex.

Question 26

True or False: cargo proteins in the trans Golgi with mannose-6-phosphate are sent to the lysosomes.

Answer 26

True. Ones without a mannose-6-phosphate in the trans Golgi are sent to the PM.

Question 27

What type of glycosylation occurs only in the Golgi?

Answer 27

O-linked oligosaccharide glycosylation

Question 28

Explain the vesicular transport model.

Answer 28

Cargo in the Golgi is carried in an anterograde (forward) direction. Subcompartment composition changes with incoming new cargo.

Question 29

Explain the cisternal progression/maturation model.

Answer 29

Golgi subcompartments are dynamic, and change as they move from cis to trans. Transport vesicles move resident Golgi proteins back.

Question 30

In the cisternal progression/maturation model, where does the new material for the cis Golgi network come from?

Answer 30

Incoming vesicles fuse together to create a new CGN, while the old one is pushed into the cisternae.