Hydrogen bonding is a type of attractive interaction that occurs between a hydrogen atom covalently bonded to a highly electronegative atom, such as oxygen, nitrogen, or fluorine, and another electronegative atom. This bond is weaker than covalent bonds but stronger than van der Waals forces, playing a crucial role in the properties of substances like water. These bonds significantly influence the structure and behavior of many biological molecules, including DNA and proteins. For example, in water, hydrogen bonds contribute to its high boiling point and surface tension, making it essential for life on Earth.