Tertiary structures refer to the three-dimensional shape of a protein that results from the folding of its amino acid chain. This folding is influenced by various interactions, including hydrogen bonds, ionic bonds, and hydrophobic interactions. The specific arrangement of these interactions determines the protein's overall structure and function. The tertiary structure is crucial for a protein's ability to perform its biological role. Changes or misfolding in this structure can lead to loss of function or diseases, such as Alzheimer's or cystic fibrosis. Understanding tertiary structures helps scientists develop treatments and therapies for these conditions.