Protein folding is the process by which a linear chain of amino acids, known as a polypeptide, transforms into a specific three-dimensional structure. This structure is crucial for the protein's function, as it determines how the protein interacts with other molecules in the body. The folding process is influenced by various factors, including the sequence of amino acids and the surrounding environment. Misfolded proteins can lead to diseases, such as Alzheimer's and Parkinson's, highlighting the importance of proper protein folding in maintaining cellular health and function.