This ordering results in physical properties such as high surface tension, high boiling point, high melting point, high heat capacity and high heat of vaporization. Water serves as a temperature regulator. Substances which donate hydrogen ions to a solution when dissolved in water are called acids. Substances which accept hydrogen ions in a water solution are called bases. Bases commonly dissociate to form hydroxyl ions which combine with hydrogen ions to form water.
Organic molecules are the basic building blocks of living organisms on earth.
Organic molecules may be viewed as a carbon core with various functional groups. Some molecules in organisms are simple organic molecules, while others are complex macromolecules. Important functional groups include alkyl, hydroxyl, sulfhydryl, carboxyl, amino, aldehyde, ketone, and phosphate groups. These groups are all derivatives of hydrocarbons. Macromolecules found in organisms include carbohydrates, lipids, proteins, and nucleic acids.