2.5 Biological Membranes (Spec)

Question 1

Membrane roles

Answer 1

Compartmentalisation - Maintain constant internal conditions -> optimum conditions of enzymes catalysing metabolic processes

Question 2

Phospholipid role

Answer 2

Prevent free movement of ions, create electrochemical gradient

Question 3

Cholesterol role

Answer 3

Regulate membrane fluidity
Increase fluidity at low temp
Decrease fluidity at high temp

Question 4

Glycoprotein/Glycolipid role

Answer 4

Cell signalling

Question 5

Extrinsic protein role

Answer 5

Form part of glycoprotein cell signalling molecule

Question 6

Intrinsic protein role

Answer 6

Carrier protein - Active transport and facilitated diffusion

Channel protein - Facilitated diffusion

Question 7

Temperature effect on membranes

Answer 7

Increasing temp
More Ek of phospholipids
Greater vibration
Cholesterol reduce vibrations to decrease fluidity
Decreasing temp
Less Ek of phospholipids
Less vibration
Cholesterol increase activity to increase fluidity

Question 8

Diffusion

Answer 8

Passive net movement of molecules down a concentration gradient from an area of high concentration to an area of low concentration

Question 9

Factors affecting diffusion

Answer 9

Temp:

Increasing increases rate, faster time