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Flashcards in Lipid Membranes Deck (15):
0

Membrane composition of lipid, protein and carbohydrate in percentage.

40% lipid
60% protein
1-10% carbohydrate

1

Function of the lipid membrane

Continuous, highly selective permeability barrier
Control of the enclosed chemical environement
Recognition of signalling molecules, adhesion proteins and for immune surveillance
Signal generation in response to stimuli (chemical or electrical)

2

Give examples of where different regions of the membrane have different functions.

Interact with the basement membrane or adjacent cells
Specialised for secretion/absorption/transport
Synapses
Conduction of electrical signals

3

What does amphipathic mean?

Has both hydrophobic and hydrophilic regions

4

What types of molecule can be found in the head of a phospholipid?
Which is rarest and why is it essential?

Choline, amine, amino acid, sugar
Sugars are the rarest, important for the synthesis of signal molecules.

5

What form of double bond introduces a kink in a fatty acid

Cis

6

What is the function of sphingomyelin

Acts as a base for glycolipids
Myelin sheath

7

Describe two types of glycolipid

Cerebroside - one simple sugar
Ganglioside - complex oligosaccharide

8

What is a liposome?

A phospholipid bilayer which fully encloses a water-filled space.

9

Describe the motion of phospholipids.

Flexion/rotation
Lateral diffusion
Flip flop (rare)

10

What is required in the diet so we can have fatty acids with kinks?

Polyunsaturated fats

11

Describe the structure of cholesterol

Rigid planar steroid ring with -OH group
Non polar hydrocarbon tail

12

Function of cholesterol

Allows the membrane to remain fluid with minimal energy (i.e. Low temperatures) and maintains rigidity at high temperatures.

13

Describe the relationship between net rate of transport and concentration difference in passive transport.

Net rate of transport is proportional to the concentration difference (linear relationship)

14

Describe the role of transport

Maintain ionic composition
Maintain intracellular pH
Regulate volume
Concentrate metabolites for fuel
Excrete waste and toxic compounds
Generate ion gradients for nerve/muscle cells