The four major classes of organic compounds are nucleic acids, lipids, carbohydrates and proteins. These compounds are found in every living organism.
An organic molecule is a molecule that contains hydrogen and carbon. The four major types of organic molecules are very large because they contain thousands of atoms of these two elements.
Nucleic acids carry genetic information, making them essential for the continuation of a species. RNA and DNA are examples of nucleic acids. Lipids are used for long-term energy storage and insulation and are also an essential component of the membranes found in living organisms. Fats and oils are common examples of lipids.
Carbohydrates serve as a source of energy in living things. Glucose, fructose and starch are just a few of the carbohydrates found in living organisms. Finally, different types of proteins have different functions. Structural proteins help the hair and skin maintain their structure, while proteins called enzymes speed up chemical reactions. The antibodies that help fight infection are also proteins.