3. Lipids and Membranes

Question 1

What are the cell membrane functions (4)?

Answer 1

• Seperate extra and intracellular.
• Send + receive signals.
• Passage of nutrients.
• Excrete waste.

Question 2

Name functions (5) of the membrane proteins?

Answer 2

• Structural Links.
• Enzyme activity.
• Transport.
• Ion channels.
• Signal receptors.

Question 3

What’s the function of the membrane carbohydrates?

Answer 3

Communication (glycoproteins and glycolipids)

Question 4

What does AMPHIPATHIC mean?

Answer 4

Contains polar (hydrophilic) and non-polar (hydrophobic) domains.

Question 5

What general shape are phospholipids?

Answer 5

Cylindrical

Question 6

What are the membrane phospholipid sub-units (4)?

Answer 6

1. Choline (hydrophylic).
2. Phosphate.
3. Glycerol.
4. 2 Fatty acid chains (hydrophobic).

Question 7

What’s the difference between the (2) fatty acid tails on a phospholipid?

Answer 7

• One is saturated.
• One is unsaturated > contains kink for cholesterol mobility.

Question 8

What is a LIPOSOME?

Answer 8

A spherical membrane-bound vesicle used for drug delivery.

Question 9

What substances can move unfacilitated across membrane (3) ?

Answer 9

• H₂O.
• Hydrophobic molecules.
• Small uncharged molecules.

Question 10

What does EXOPLASM mean?

Answer 10

Outer surface of plasma membrane.

Question 11

What types (3) of protein exists in the membrane?

Answer 11

• Integral.
• Peripheral.
• Lipid anchored.

Question 12

Can amphipathic protein structures pass through the membrane?

Answer 12

Multiple times > alpha helices.

Question 13

What are MONOTOPIC proteins?

Answer 13

Proteins permanently attached to one side of membrane.

Question 14

What percentage of membrane mass is carbohydrate?

Answer 14

10%

Question 15

What is a LIPID RAFT?

Answer 15

Specialised organised centres part of the cell membrane.

Question 16

What makes up lipid rafts?

Answer 16

Phospholipids, Proteins, cholesterol.

Question 17

What is the function of the lipid raft?

Answer 17

Signalling.

Question 18

What are CAVEOLAE?

Answer 18

Lipid raft, membrane folds that engulf proteins.

Question 19

What do the CAVEOLIN protein family do?

Answer 19

Form and maintain CAVEOLAE.

Question 20

What are MICROVESICLES?

Answer 20

Plasma membrane fragments.

Question 21

What’s the function of the FLIPPASE ENZYME?

Answer 21

Transport phospholipids from membrane > cytosol.

Question 22

What’s the function of the SCRAMBLASE ENZYME?

Answer 22

Translocates phospholipids.

Question 23

What’s the function of the FLOPPASE ENZYME?

Answer 23

Transports phospholipids from cytosol > membrane.

Question 24

What are EXOSOMES?

Answer 24

Extracellular vesicles - used for communication + exporting waste.

Question 25

What does METASTASIS mean?

Answer 25

Spread of cancer from one part of the body to another.

Question 26

What substances can move through the membrane unfacilitated (3)?

Answer 26

• Water.
• Hydrophobic molecules.
• Small uncharged molecules.