Carbon is the most abundant element in humans and bacteria. Carbon is compatible with the greatest number of different elements because of its tetravalence. Carbon shares four electrons. This means it can create single, double, and triple covalent bonds. Carbon skeletons occur when two or more carbon atoms bond to each other. This skeleton contributes to the great diversity of molecules that are carbon based. The simplest organic molecule is a hydrocarbon, when only a hydrogen and carbon atom is bonded.
When carbon is bonded to one or more different elements it creates different functional groups. The hydroxyl group consists of alcohols that are water-soluble and polar. Carboxyl group is made of carboxylic acids that release hydrogen ions when dissociated. The amino group is the building block of protein. The cross-links of sulfhydryls stabilize proteins. And phosphates are required for energy transfer.
Because of carbon's unique valence shell it can create different isomers. Structural isomers have different arrangement of atoms usually in the location of double bonds. Geometric isomers have the same covalently bonded atoms but have different spatial arrangement. Enantiomers are mirror images of each other but one is usually biologically inactive.
The greenhouse effect causes global warming, the increase of global temperature. Carbon plays a part in this process. When carbon bonds to two oxygen atoms it creates carbon dioxide. The greenhouse effect the warming of planet Earth due to the accumulation of carbon dioxide in the atmosphere. This accumulation of carbon dioxide absorbs infrared radiation and slows its escape from the Earth causing a slight rise in temperature. .