Molecular interactions refer to the forces that hold molecules together or cause them to interact with one another. These interactions can include hydrogen bonds, ionic bonds, van der Waals forces, and hydrophobic interactions. They play a crucial role in determining the structure and function of biological molecules, such as proteins and nucleic acids. Understanding molecular interactions is essential in fields like biochemistry and pharmacology. For instance, the way a drug binds to its target protein can influence its effectiveness. By studying these interactions, scientists can design better medications and understand various biological processes, including cell signaling and enzyme activity.