Final answer:
A tripeptide can contain a minimum of zero and a maximum of three negative charges, determined by whether the amino acids aspartate or glutamate are included in its sequence.
Step-by-step explanation:
A tripeptide, which is a chain consisting of three amino acid units, can contain a minimum and maximum number of negative charges based on the presence of specific amino acids with negatively charged side chains. These negatively charged side chains are typically found in the amino acids aspartate and glutamate. Considering that a tripeptide is made up of three amino acid residues, the minimum number of negative charges is zero if none of the amino acids possess these charged side chains, and the maximum is three if each of the residues is either aspartate or glutamate.
Therefore, a tripeptide can contain a minimum of zero and a maximum of three negative charges. This accounts for the negative charges contributed by the side chains and does not consider the possible ionization states of the amino and carboxyl termini at varying pH levels.