AP BIOLOGY

Detailed explanation-1: -Degradation of peptide bond involves a reaction in which breaking of the peptide bonds between the molecules occurs. Hydrolysis (addition of water) is the reaction used for the degradation of the peptide bond.

Detailed explanation-2: -Sortases are a class of bacterial enzymes that possess transpeptidase activity. It is their ability to site-specifically break a peptide bond and then reform a new bond with an incoming nucleophile that makes sortase an attractive tool for protein engineering.

Detailed explanation-3: -A protein becomes denatured when its normal shape gets deformed because some of the hydrogen bonds are broken. Weak hydrogen bonds break when too much heat is applied or when they are exposed to an acid (like citric acid from lemon juice).

Detailed explanation-4: -During the denaturation process of protein, the secondary and tertiary structure of protein will be changed but the peptide bond of the primary structure remains constant. Because, the denaturation reaction is not strong and its energy is not enough to break the peptide bond.

Detailed explanation-5: -Amino acids undergo hydrolysis by cleaving the bond between an amino acid from the carbon atom of one alpha carbon and nitrogen atom linked to the alpha carbon of another amino acid; the bond is called a peptide bond. Therefore, the correct answer is D. peptide bond.