The functional structure of a protein is its structure, which is ultimately determined by the
a. tertiary; primary structure
b. primary; ions it possesses
c. tertiary; concentration of phosphates
d. monogamous; first amino acid on the terminal sequence

A.

Explanation:

The tertiary structure of proteins is related to the interactions between the amino acids of the primary structure. Thus, these interactions give it a specific three-dimensional configuration which is very sensitive to functionality.

For example, allosteric inhibitions are related to this concept. When the inhibitor changes the tertiary structure of the protein it loses all activity and for the catalysis of the reaction.

Thus, the primary structure (which is related to the specific sequence of amino acids) will determine the tertiary structure since the chain folds will be a consequence of intra-amino acid interactions.

Answer

A. tertiary; primary structure

Explanation.

The tridimentional geometry of a protein is known as tertiary structure. The localization of turns inside the protein, determined by the presence of aminoacids such as Pro, Thr, Ser and Gly are examples of the influence of the primary structure in the tertiary structure of a protein. Also, the interactions between aminoacids inside the polipeptidic chain allow the protein have a specific tertiary structure.