Which of the following may be classified as a hydrophobic amino acid at pH 7.0?

Amino acids having nonpolar side chains: These include Alanine, Valine, Leucine, Isoleucine, Methionine, Proline, Phenylalanine, and Tryptophan. These groups are hydrophobic (water repellant) and lipophilic. Therefore, the pas of proteins made up of these amino acids will be hydrophobic in nature.Ref: DM Vasudevan - Textbook of Biochemistry, 6th edition, page no: 20-21