Question

in some cases, a single amino acid substitution can cause a protein to lose its biological activity. in other cases, a single amino acid substitution causes no change to a proteins biological activity. which statement can best be used as evidence to support an explanation for these observations? noncovalent interactions between atoms in a polypeptide chain stabilize the secondary, tertiary, and quaternary levels of its structure. amino acids found in the proteins of living organisms have many similarities, including an alpha - amino group and an alpha - carboxyl group. amino acids are covalently linked through peptide bonds to form the primary structure of a protein. each amino acid side chain has properties that are very different from those of some side chains and very similar to those of others. amino acids occur as optical isomers, but only one isomer of each is found in the proteins of most of the organisms on earth.

Explanation:

The key is understanding how amino - acid substitution affects protein function. Different side - chain properties of amino acids can explain why some substitutions change function and some don't. If side chains have similar properties, substitution may not affect function; if different, it can disrupt function.

Answer:

Each amino acid side chain has properties that are very different from those of some side chains and very similar to those of others.