Final answer:
To identify amino acids in a peptide, examine the sequence from the N-terminal to the C-terminal. Understanding the difference between an amino acid and a peptide, and recognizing the role of peptide bonds, is crucial to determining the peptide's structure and function.
Step-by-step explanation:
To determine which amino acids are present in a peptide, one must examine the sequence provided, which goes from the N-terminal to the C-terminal end. For example, the peptide lys-val-phe-gly-arg-cys has a lysine (lys) at the N-terminal and a cysteine (cys) at the C-terminal. Similarly, the peptide asp-arg-val-tyr-ile-his-pro-phe begins with aspartic acid (asp) at the N-terminal and ends with phenylalanine (phe) at the C-terminal.
An amino acid is distinct from a peptide in that it is a monomer that makes up peptides and proteins, whereas a peptide is a chain of two or more amino acids linked by amide bonds. A dipeptide has one amide bond; therefore, a tripeptide would have two. This is because peptides are named for the number of amino acids they contain minus one, corresponding to the number of amide bonds formed.
In summary, the sequence of amino acids dictates the structure and function of the peptide or protein, with the peptide bond being a key player in the formation of these vital biological molecules.