Final answer:
The hydrophobic effect refers to the tendency of nonpolar molecules or molecular regions to aggregate away from water, primarily caused by the inability of these groups to participate in hydrogen bonding with water and by London dispersion forces.
Step-by-step explanation:
The hydrophobic effect is a phenomenon observed in molecular biology and chemistry where nonpolar molecules or parts of molecules aggregate together in aqueous environments. This occurs because water molecules are polar and can form hydrogen bonds with each other, but they cannot do so with nonpolar substances like hydrophobic molecules. In a physiological medium predominantly water, these nonpolar groups, such as those found in proteins, are repelled by water and tend to stay in the interior of the protein structure, minimizing their contact with water.
Moreover, the hydrophobic interaction can be considered a manifestation of London dispersion forces, a type of weak intermolecular force that even nonpolar molecules can exhibit. While dispersion forces arise due to the momentary dipoles in nonpolar molecules, hydrophobic interactions are particularly due to the exclusionary behaviour of water molecules around nonpolar entities, effectively pushing these hydrophobic groups together. As a result, proteins and other complex molecules fold in such a way that their nonpolar (hydrophobic) regions are buried inside, away from the aqueous surroundings.