What type of molecules would you expect to be able to cross the cell membrane and enter the cell? Why?

Question

All input is greatly appreciated!! =)

Answer 1

1. Hydrophobic molecules (hydrocarbons and oxygen) can cross with ease because they can dissolve in the lipid bilayer.
2. Small polar (uncharged) molecules will pass (water and carbon dioxide).
3. Large polar (uncharged) molecules will not pass (glucose).
4. Ions will not readily pass (H+, Na+, Cl-).

Answer 2

These molecules should be able to cross easily:
1. little - can slip through small spaces
2. no charge - won't be repelled by any charges in the membrane
3. soluble in lipids - dissolve their way through the phospholipid bilayer