Permeability of membranes Flashcards
1
Q
How do lipid-soluble substances move through the membrane?
A
Vitamin A and small molecules e.g. Oxygen dissolve in the phospholipid and diffuse across the membrane
2
Q
What type of substance moves through the membrane more easily and why?
A
Lipid-soluble substances because the membrane is hydrophobic.
3
Q
How do water-soluble substances move through the membrane ?
A
Polar molecules and ions cannot readily diffuse through the phospholipids and must pass through intrinsic protein molecules which form water-filled channels.
Therefore the membrane is selectively permeable to water and some solutes.
