Cell bio chapter 12

Proteins that leave the rough ER travel directly to:

the Golgi

All proteins leaving the Golgi are trafficked to the cell membrane.

False

Proteins trafficked in vesicles are referred to as:

cargo proteins

To maintain balance within the endomembrane system, both anterograde and retrograde vesicular traffic is required.

True

Sar1 is activated by:

GEF

COPII is found on the luminal side of the rough ER.

False

When do Sar1 proteins hydrolyse their GTP?

after the vesicle has completely budded off from the rough ER

When Sar1 proteins hydrolyze their GTP, COPII proteins leave the vesicle.

True

Docking begins when ___ on the vesicle binds to ___ in the target membrane.

Rab-GTP, a tethering protein

Fusion begins when ___ on the vesicle binds to ___ in the target membrane.

a v-SNARE, a t-SNARE

The energy released from ATP hydrolysis is not used DIRECTLY by the SNAREs during vesicle fusion.

True

Which of the following is an ATPase?

NSF

The Golgi is composed of many interconnected flattened sacs called cisternae.

True

There are no discrete boundaries between the cis-, medial-, and trans-Golgi networks so it’s difficult to say precisely where one network ends and the next begins.

True

The first trans cisterna is formed by the fusion of vesicles arriving from the rough ER.

False

Cargo proteins remain in the same cisterna throughout their entire journey through the Golgi.

True

Golgi vesicles transport:

resident Golgi proteins.

COPI coat proteins are used for vesicles moving from the Golgi back to the rough ER.

True

Many of the modifications that take place in the Golgi involve the addition, removal, or rearrangement of sugar molecules in the 10-sugar

True

What is the function of glycosidases?

to remove sugars

Vesicles leaving the trans-Golgi network and heading to endosomes or lysosomes are formed by which of the following coat proteins?

clathrin

Which of the following vesicle coat proteins interacts with adaptor proteins during vesicle formation?

clathrin

How do cell membrane proteins arrive to the cell membrane?

exocytosis

Which of the following is sometimes referred to as cell drinking?

pinocytosis

Which of the following is sometimes referred to as cell eating?

phagocytosis

All incoming vesicles from the cell membrane and extracellular solution are trafficked to:

endosomes.

The acidic environment within endosomes:

allows the soluble cargo proteins to dissociate from their membrane receptors.

Which of the following possesses the most acidic lumen?

lysosome.

Oligosaccharides attached to proteins in the lysosomal membrane protect these membrane glycoproteins from degradation from lysosomal enzymes.

True

Vesicles arrive at the cis-Golgi network from:

ERE