In the tripeptide formation of cysteine, alanine, and tyrosine, the bond that forms between the amino acids is called a peptide bond.
A peptide bond is a type of covalent bond that connects two amino acids in a protein or peptide chain. It forms through a condensation reaction between the carboxyl group (-COOH) of one amino acid and the amino group (-NH2) of another amino acid. During the condensation reaction, a water molecule is eliminated, and the resulting bond between the carbon and nitrogen atoms is called a peptide bond.
In the case of the tripeptide formation of cysteine, alanine, and tyrosine, two peptide bonds are formed: one between cysteine and alanine, and another between alanine and tyrosine. These peptide bonds connect the three amino acids together, forming a tripeptide chain.