Transport Across Membranes

Question 1

How do you calculate the rate of transport across a cell membrane?

Answer 1

Surface area x concentration gradient/ thickness of membrane

Question 2

What is the effect of increasing temperature on rate of transport?

Answer 2

• increases rate of diffusion
• due to increase of kinetic energy

Question 3

What is the effect of increasing the size of molecule on the rate of transport?

Answer 3

• decreases rate of transport
• smaller molecules diffuse faster than larger ones

Question 4

What is the effect of lipid solubility of molecule on the rate of transport?

Answer 4

• lipid soluble, non polar molecules diffuse faster than water soluble, polar molecules
• due to phospholipid bilayer (hydrophobic)