Hydrophobic interactions refer to the tendency of nonpolar substances to avoid contact with water. When placed in an aqueous environment, these nonpolar molecules cluster together to minimize their exposure to water. This behavior is crucial in biological systems, as it helps to stabilize the structure of proteins and cell membranes. In the context of biochemistry, hydrophobic interactions play a significant role in the folding of proteins. The nonpolar regions of a protein tend to fold inward, away from water, while polar regions remain on the surface. This arrangement is essential for the protein's functionality and overall stability.