Final answer:
The folded-three dimensional conformation of a polypeptide is known as its tertiary protein structure, which is crucial for the protein's biological function and stability.
Step-by-step explanation:
The folded-three dimensional conformation of a polypeptide represents its tertiary protein structure. This structure is a result of the polypeptide chain folding into a compact, three-dimensional shape due to interactions between the amino acid side chains.
It is this intricate folding pattern due to side chain interactions that determines the protein's biological function. The tertiary structure is essential since it contributes to the protein's stability and function.
When this structure is disrupted, through changes in environment such as pH or temperature, the protein can become denatured, losing its functionality.