Macromolecules include: carbohydrates, lipids, proteins and nucleic acids. Macromolecules consists of smaller molecules joined together chemically. Carbohydrates, which are sugars and starches, contain carbon, hydrogen, oxygen and the ratio of hydrogen to oxygen is 2:1. Simple sugars are glucose and fructose and they are made of a single monomer. However, starch and glycogen which are polysaccharides, consist of many sugar monomers joined together. Lipids consist of carbon, hydrogen and oxygen but there is not a 2:1 hydrogen to oxygen ratio. The molecules are very large and consist of fatty acids and glycerol. Examples are fats, oils and waxes. Proteins are made of smaller subunits called amino acids, joined together to make a polymer. Proteins contain carbon, hydrogen and oxygen as well as nitrogen. An amino acid, the building block of protein, contains a hydrogen atom, a carboxyl group, an amino group and a variable or side chain. In nature, there are 20 different amino acids. Nucleic acids include both RNA and DNA. DNA contains the genetic information of an organism and RNA is involved in transcription and translation of the DNA into proteins the organism needs. A subunit of a nucleic acid is a nucleotide. In DNA, it consists of a phosphate group, a sugar called deoxyribose and one of four possible nitrogenous bases--Adenine, thymine, cytosine or guanine. DNA can be recognized as a double helix with each side complementary to the other side. RNA is a single stranded molecule. There is a different sugar in the molecule as compared to DNA. This sugar is called ribose and one of four bases is present--adenine, guanine, cytosine or uracil.