When not part of a polypeptide, which of the following amino acids have the potential to participate in hydrogen bonding with water? Choose ALL that apply.

a. Alanine

b. Arginine

c. Leucine

d. Lysine

Option b and d

Explanation:

When not part of a polypeptide, amino acids like Arginine and lysine which contains amino acids in active sites of their side chains can potentially take part in hydrogen bonding with water molecules.

Other two amino acids in the options are Alanine and leucine and these are hydrophobic amino acids.

These amino acids contains in their side chains groups that are non-polar and can't take part in hydrogen bonding with water or other polar entities.