1.1.2 Biological Molecules: Reactions

• A covalent bond is the sharing of two or more electrons between two atoms The electrons can be shared equally forming a nonpolar covalent bond or unequally (where an atom can be more electronegative δ-) to form a polar covalent bond
• Covalent bonds are very stable as high energies are required to break the bonds
• Multiple pairs of electrons can be shared forming double bonds (e.g. unsaturated fats C=C) or triple bonds
• A condensation reaction occurs when monomers combine together by covalent bonds to form polymers (polymerisation) or macromolecules (lipids) and water is removed
• In the hydrolysis of polymers, covalent bonds are broken when water is added