Lipid Membranes Flashcards Preview

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Flashcards in Lipid Membranes Deck (15)
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0
Q

Function of the lipid membrane

A

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)

1
Q

Membrane composition of lipid, protein and carbohydrate in percentage.

A

40% lipid
60% protein
1-10% carbohydrate

2
Q

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

A

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

3
Q

What does amphipathic mean?

A

Has both hydrophobic and hydrophilic regions

4
Q

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

A

Choline, amine, amino acid, sugar

Sugars are the rarest, important for the synthesis of signal molecules.

5
Q

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

A

Cis

6
Q

What is the function of sphingomyelin

A

Acts as a base for glycolipids

Myelin sheath

7
Q

Describe two types of glycolipid

A

Cerebroside - one simple sugar

Ganglioside - complex oligosaccharide

8
Q

What is a liposome?

A

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

9
Q

Describe the motion of phospholipids.

A

Flexion/rotation
Lateral diffusion
Flip flop (rare)

10
Q

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

A

Polyunsaturated fats

11
Q

Describe the structure of cholesterol

A

Rigid planar steroid ring with -OH group

Non polar hydrocarbon tail

12
Q

Function of cholesterol

A

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

13
Q

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

A

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

14
Q

Describe the role of transport

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