Which factor primarily determines the functional three-dimensional shape (conformation) of a mature protein?

💡 Explanation:

The primary structure of a protein is the unique, linear sequence of amino acids linked by peptide bonds. This sequence dictates the formation of secondary structures (alpha-helices and beta-sheets), which in turn determines the final tertiary structure (the unique 3D folding). Therefore, the amino acid sequence is the fundamental determinant of a protein's functional conformation. While environment (A), quaternary structure (C, if applicable), and cofactors (D) influence stability and activity, they do not primarily determine the inherent folding pattern.