Chapter 12 Transport Across Membranes

Question 1

What factors influence a molecules ability to diffuse, unaided across a lipid bilayer?

Answer 1

Small size, hydrophobic and non-polar are most likely to diffuse across the lipid bi-layer.

Large, hydrophilic, polar are will diffuse more slowly.

Charged molecules cannot diffuse across the bilayer.

The most important attribute for diffusing across the lipid bilayer

Question 2

Can small non-polar molecules like O2, CO2, N2, and steroid hormones cross the lipid bilayer unassisted?

Answer 2

Yes, and easily.

Question 3

Can small uncharged polar molecules like H2O, ethanol and glycerol cross the lipid bilayer unassisted?

Answer 3

Yes, not as quickly as non polar molecules.