Chapter 5 (Plasma Membranes)

Question 1

What is the difference between an extrinsic and an intrinsic protein?

Answer 1

Extrinsic proteins are only partially imbedded into the plasma membrane, while intrinsic proteins span the whole membrane.

Question 2

What are glycoproteins?

Answer 2

Type of intrinsic protein. Contain attached carbohydrate chains. Are involved in cell adhesion and as receptors.

Question 3

What are glycolipids?

Answer 3

Lipids with attached carbohydrate chains. Also called antigens

Question 4

How does temperature affect membrane structure?

Answer 4

Increases kinetic energy of phospholipids, causing the membrane to be more fluid and increasing permeability.
Carrier and channel proteins can also be denatured, affecting permeability.

Question 5

How do solvents affect membrane structure?

Answer 5

Water is a polar solvent needed in the formation of a membrane, as the phospholipid tails move away from water.
When organic solvents are less polar than water or non polar, such as alcohol and benzene respectively, then they disrupt cell membranes, increasing permeability.

Question 6

What is the term used for when an animal cell has a high water potential then bursts?

Answer 6

Cytolysis

Question 7

What is the term used for when an animal cell loses water by osmosis and begins to ‘pucker’?

Answer 7

Crenation