The study of biology requires an understanding of simple organic chemistry and simple biological chemistry. Carbohydrates , lipids , proteins , and nucleic acids , the players in molecular biology, are themselves composed of smaller building blocks. This chapter contains a review of important chemical interactions and concepts you will encounter in this course. This section provides a quick review of chemical bonds. Once formed, covalent bonds rarely break spontaneously.
Water is perhaps the most obvious example of a molecule with partial charges.
Oxygen, because of its high electronegativity, attracts the electrons away from the hydrogen atoms, resulting in a partial negative charge on the oxygen and a partial positive charge on each of the hydrogens. 1.2 Hydrogen Bonds Hydrogen bonds are formed when a hydrogen atom is shared between two molecules. Hydrogen bonds have polarity. One example, shown above, involves the hydrogen bonding between water molecules. 1.3 Ionic Bonds Ionic bonds are formed when there is a complete transfer of electrons from one atom to another, resulting in two ions, one positively charged and the other negatively charged.