Final answer:
The statement is false; disulfide bridges do not influence primary protein structure. They stabilize the protein's tertiary and quaternary structures by forming covalent bonds between sulfur atoms in cysteine residues.
Step-by-step explanation:
The statement that disulfide bridges influence primary protein structure is false. The primary structure of a protein is simply the sequence of amino acids in a polypeptide chain, determined by the gene encoding the protein. Disulfide bridges, however, play an essential role in stabilizing the tertiary structure of proteins, which is the overall folded 3D structure of the entire polypeptide chain, and the quaternary structure when they form between different polypeptides. Disulfide bridges are covalent bonds between sulfur atoms in cysteine residues within a polypeptide or between different polypeptides in a protein complex.
During the folding process, cysteine residues that are far apart in the primary sequence can end up close together, enabling the formation of disulfide bridges. This oxidative linking of sulfhydryl groups (-SH) to form disulfide bonds (-S-S-) stabilizes the three-dimensional conformation of the protein. In the context of hemoglobin, for example, different polypeptides (alpha and beta chains) come together to form its functional quaternary structure, with potential disulfide bridges contributing to its stability.