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1. When part of a polypeptide, which of the following amino acids have the poten

ID: 149683 • Letter: 1

Question

1. When part of a polypeptide, which of the following amino acids have the potential to participate in hydrogen bonding with water? Choose ALL that apply.

Alanine, Arginine, Asparagine, Leucine, Phenylalanine, Valine

2. 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.

Alanine, Arginine, Leucine, Lysine

1. When part of a polypeptide, which of the following amino acids have the potential to participate in hydrogen bonding with water? Choose ALL that apply.

Alanine, Arginine, Asparagine, Leucine, Phenylalanine, Valine

2. 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.

Alanine, Arginine, Leucine, Lysine

Explanation / Answer

For a hydrogen bond to be formed ,the amide (N) and carbonly(O) (which are ectronegative atoms) have to interact with same hydrogen. In this interaction the H atomis attached to the donar atom via covalent bond and interacts favourably with the acceptor atom.

Ans 1. When part of a polypeptide, amino acids like Arginine and Asparagine have the potential to participate in hydrogen bonding with water as these two amino acids are charged and polar respectively. Asparagine have an amide group (N) that participate in hydrogen bonding.

Ans 2. When not part of a polypeptide, amino acids like Arginine and lysine which are charged amino acids with side chains have the potential to participate in hydrogen bonding with water. Other 2 amino acids given here: Alanine and leucine are hydrophobic(water repelling) amino acids. The side chains of these amino acids are non-polar and cannot form hydrogen bonds with water or any other polar entites.This is the reason the hydrophobic amino acids (Ala, Ile, Leu, Met,Phe,Val,Peo and Gly) are norally found to build the protein core.