Diffusion rate through lipid bilayer

[Puchinita5]

Homework Statement

I had a homework problem that asked "Which compound in each pair will diffuse with a higher rate through lipid bilayer? a) Asp or Glu; b) Thymidine or TMP; c) glucose or glucosamine"

And i figured the compound that is most nonpolar will go through fastest.

So I said that Glutamic acid would go through faster than aspartic acid because of the extra carbon; Thymidine would go through faster than TMP because the phosphate make TMP more polar; and I said glucosamine would go through faster because the amine group is less polar than the OH group that would be on glucose.

However, the answers say that glucose goes through faster than glucosamine. WHY?

Homework Equations

The Attempt at a Solution

 

[Nino MMP]

I don't understand why glucose would go through faster than glucosamine. I thought that the amine group on glucosamine would make it less polar and therefore faster?