are carbs protein and lipids food groups or molecules
All living things contain organic macromolecules: Lipids, proteins, carbohydrates and nucleic acids. Characteristic for these organic molecules is that they are made up of only a small number of elements: carbon, hydrogen, oxygen, and to smaller amounts nitrogen, phosphorus and sulfur. There are 20 different amino acids that combine to form polypeptides (proteins). 2  The different amino acids are similar in structure: at the center of the molecule is the alpha carbon that is connected to an amino group, a carboxyl group, a hydrogen atom and the R group (the side chain).