Organic Compound

Carbon is the key element of organic compounds. All organic compounds contain carbon. However, all substances containing carbon are not organic compounds. Carbon dioxide and carbonic acid (H2CO3) are not organic compounds because the primary bonding is between carbon and oxygen. In organic compounds the main bonds are carbon-to-carbon and carbon-to-hydrogen. Methane (CH4) is and organic compound because of its carbon-hydrogen bonds. It was formerly believed that organic compounds could be made only in living systems. The four main categories of organic compounds are carbohydrates, lipids, proteins and nitrogen-base derivatives. These substances are present in varying quantities in different cells. The inorganic matter is mainly water. It far outweighs organic substances. In general, plant cells contain less organic matter and more water per unit weight than animal cells.