Chapter 18.3, Problem 18.7KCP

(a)

Interpretation Introduction

Interpretation:

Reason for side chain in valine is nonpolar and in serine is polar has to be identified.

Concept introduction:

Many amino acids are linked together through amide bonds to form a biologically large molecule known to be proteins.

Amino acid had both amino functional group and carboxyl functional group in a molecule.

Amino functional group is $(-N{H}_2)$ and carboxyl functional group is $(-COOH)$ and a $R$ group is considered as side chain, when all these are bonded to same carbon atom.

The amino acids are further classified into polar and non-polar amino acid.

Polar amino acid are those that contain groups that are either charged at physiological $pH$ or groups that are able to participate in hydrogen bonding.

Nonpolar amino acids are those with alkyl hydrophobic group which cannot enter in hydrogen bonding.

(b)

Interpretation Introduction

Interpretation:

Amino acid that has hydrophilic and hydrophobic side chain has to be identified.

Concept introduction:

Many amino acids are linked together through amide bonds to form a biologically large molecule known to be proteins.

Amino acid had both amino functional group and carboxyl functional group in a molecule.

Amino functional group is $(-N{H}_2)$ and carboxyl functional group is $(-COOH)$ and a $R$ group is considered as side chain, when all these are bonded to same carbon atom.

The non-polar side chain are again classified into hydrophobic (water hating) and hydrophilic (water loving).