Which of the following compounds is hydrophobic?

Question

Which of the following compounds is hydrophobic
a, hemoglobin
b. glucose
c. RNA
d. glycerol
e. amino acid

Answer 1

C. RNA, is denatured by the hydrophibic interaction with water.

A. Hemoglobin is in blood, which also has water in it
B. Sugar dissolves nicely in water, or coffee
D. Glycerol dissolves in water, I use it to make monster bubble solution.
E. Most low molecular weight organic acids dissolve in water. You generally only have problems with organic acids when the R group gets large ( >C10) or takes on an aliphatic character (a single long chain of fully saturated hydrocarbons)

Answer 2

C Lysine is polar because it's side chain has a nitrogen atom in it. Serine has OH, which would make it polar. Nitrogen and oxygen make an amino acid polar because these nitrogen and O are electronegative (have a strong affinity for electrons). These atoms would therefore draw electrons towards itself, making the bonds around it polar. Arginine and Aspartic Acid also have polar side groups. Phe is attached to a carbon ring, which is generally nonpolar. Carbon is not very electronegative.