Proteins are the macromolecules that preform almost all of the cell's work.
Proteins are used for energy, communication, ezymatic activity, communication, transport, and many other things. Proteins are very complex and versitile macromolecules. Proteins are involved in almost every cellular process and come in many shapes and sizes. However all proteins are made up of only twenty amino acids. From a chemical point of view proteins are just heterogenous polymers composed of the twenty amino acids.