Final answer:
Protein structure is determined by its sequence of amino acids, which form the primary structure and dictate the secondary, tertiary, and quaternary structures. Secondary structures include the alpha-helix and beta-sheet, which lead to the final 3D conformation essential for protein function.
Step-by-step explanation:
The conformation or structure of a protein is fundamentally determined by its primary structure, which is the unique sequence of amino acids in its polypeptide chain(s). This sequence is crucial as it dictates the higher levels of protein structure and ultimately the protein's function, which includes reactions such as enzyme catalysis, the transport of molecules, and many other cellular functions. The secondary structure of a protein refers to regularly repeating local structures, primarily the alpha-helix and beta-sheet, which are stabilized by hydrogen bonds between the amino and carboxylic groups of the amino acid backbone.
Tertiary structure is the overall three-dimensional shape of a single polypeptide chain, and quaternary structure describes the arrangement and interaction of multiple polypeptide subunits in a protein that has more than one. These higher-level structures are stabilized by various interactions, including hydrogen bonding, disulfide bridges, hydrophobic interactions, and ionic bonds. Any changes to the primary structure can lead to alterations in these complex structures, affecting the protein's functionality.