Final answer:
The effect of an individual amino acid on the secondary structure of proteins can vary, with some amino acids potentially causing significant changes in protein function and structure, as seen in the case of sickle cell trait.
Step-by-step explanation:
The statement regarding the role of an amino acid in the secondary structure of proteins could be considered false as the effect of a single amino acid can vary. While some amino acids may not have a significant effect, others can markedly impact protein structure and function. For instance, the substitution of glutamic acid with valine at the sixth position of the β-chain in hemoglobin results in sickle cell hemoglobin (HbS), characteristic of sickle cell trait, demonstrating the profound effect an amino acid can have.
The secondary structure, which includes the α-helix and β-pleated sheets, is vital as it is stabilized by hydrogen bonds and dictates the protein's function to a significant extent. Distinctive protein folding into tertiary and quaternary structures is critical for the biological role a protein may serve. Therefore, the precise arrangement of amino acids in the secondary structure is crucial for protein functionality.