Final answer:
The individual polypeptide chains in a multi-subunit protein each have their own unique primary, secondary, and tertiary structures. The primary structure consists of the specific amino acid sequence, whereas the secondary structure includes local folding such as alpha-helices and beta-pleated sheets, and the tertiary structure is the 3D arrangement of the polypeptide.
Step-by-step explanation:
The correct answer is A) True, they have their own unique structures. Each polypeptide in a multi-subunit protein does indeed have its own primary, secondary, and tertiary structures. To recap, the primary structure is the sequence of amino acids in the polypeptide chain. The secondary structure refers to the local folding within the polypeptide, often into configurations such as alpha-helices and beta-pleated sheets. Lastly, the tertiary structure involves the overall three-dimensional folding of the polypeptide, which is crucial for the molecule's function. When multiple polypeptide chains (each with their own set of these structures) join, they form the quaternary structure, contributing to the function of complex proteins like hemoglobin that has four polypeptide subunits.