Protein folding is the process by which a linear chain of amino acids, known as a polypeptide, acquires its functional three-dimensional structure. This structure is crucial for the protein's ability to perform its specific biological functions. The sequence of amino acids determines how the chain folds, influenced by various interactions such as hydrogen bonds, ionic bonds, and hydrophobic effects. Proper protein folding is essential for cellular function, as misfolded proteins can lead to diseases like Alzheimer's and Parkinson's. Cells have mechanisms, including chaperone proteins, that assist in the correct folding of proteins and help prevent aggregation of misfolded proteins, ensuring cellular health and function.