Membrane Ultrastructure

Question 1

What is the function of the vesicles?

Answer 1

Transports and stores materials. These are membrane bound organelles.

Question 2

2 reasons why membranes and their proteins are needed?

Answer 2

1) Cell Polarisation

2) Compartmentalisation

Question 3

What is the Diffusion Potential?

Answer 3

Voltage which exactly opposes net diffusion of a particular ion through that membrane (e.g. Sodium ion leaves, depolarised, so positive Diffusion Potential)

Question 4

What is the overall membrane potential?

Answer 4

Result of all of the diffusion potentials

Question 5

Two sides of Epithelia?

Answer 5

1) Basolateral: Bits on side and base

2) Apical: Face lumen of tube/external environment

Question 6

Method of internalising extra-cellular signal?

Answer 6

Signal Transduction

Question 7

How do G-Protein Coupled Receptors work?

Answer 7

1) Receptor: Primary specificity

2) 3 G proteins: Give further specificity, determines second messenger

Question 8

Why is a dramatic change in pH bad? (2)

Answer 8

1) Damage proteins

2) Inhibits cell function

Question 9

What happens in Acidosis (e.g. with Ca2+)

Answer 9

More acidic, so proteins ‘suck up’ and bind to H+ to fight against acid, less Ca2+ can bind

Question 10

What happens if Temperature wrong?

Answer 10

1) Cold: Proteins slow and membrane less fluid

2) Hot: Denature and increased membrane fluidity