Lecture 7

Question 1

What is the structural difference between the smooth ER and the rough ER?

Answer 1

Rough ER looks like sheets or disks of bumpy membranes while smooth ER looks more like tubes. Rough ER is called rough because it has ribosomes attached to its surface.

Question 2

What is the function of the smooth ER?

Answer 2

• metabolism of carbohydrates
• lipid synthesis for membranes
• detoxification of drugs and poisons
• storage of calcium ions
• extensive sER in cells active in these processes
• the amount of sER can be increased or decreased to meet demand.

Question 3

What is the function of the rough ER?

Answer 3

• involved in protein synthesis
• secreted and membrane-bound proteins enter the lumen (interior) of the rER
• processed via the endomembrane system.

Question 4

What is the Golgi complex?

Answer 4

A series of membrane sacs and associated vesicles.

Question 5

Where do vesicles enter and leave the Golgi complex?

Answer 5

Enter from the cis face and leave from the trans face.

Question 6

What is the function of the Golgi?

Answer 6

• glycosylation of proteins (adding or modifying carbohydrates, important for cells surface proteins)
• sorting proteins (adds markers to send proteins to vesicles)
• directing vesicle trafficking (with markers)

Question 7

What is a retrieval tag?

Answer 7

Directs proteins back.

Question 8

By what process are hormones and neurotransmitters released from the cell?

Answer 8

Exocytosis

Question 9

By what process is ‘food’ taken into the cell?

Answer 9

Endocytosis

Question 10

What is pinocytosis?

Answer 10

The non-selective uptake of solutes.

Question 11

What is the function of a lysome and how do they work?

Answer 11

To digest cellular materials using hydrolytic enzymes, or to undergo autophagy (whole cell destruction).