Carbon and the Molecular Diversity of Life The study of carbon compounds

Carbon Is the backbone of biological molecules Proteins, DNA, carbohydrates are molecules which are all composed of carbon atoms bonded to atoms of other elements such as H, O, N, S, and P.

Carbon enters the biosphere through plants

Plants absorb CO2 and use it to make sugars during photosynthesis

Coal deposits were formed from the bodies of plants and animals over millions of years

Ocean water stores 50% of atmospheric CO2

Coal is burned to produce electricity, which releases more CO2 into the atmosphere.

Organic Chemistry The branch of chemistry that specializes in the study of carbon containing compounds.

Carbon-based life forms

Carbon has a total of 6 electrons, with 2 in the first electron shell and 4 in the second shell, the valence shell.

Carbon usually completes its valence shell by sharing its 4 electrons with other atoms in covalent bonds so that 8 electrons are present.

Tetravalence Meaning that each carbon atom can act as an intersection point from which a molecule can branch off in up to four directions. C

Carbon can form single, double or triple bonds Carbon can form single, double or triple bonds. Each line in the diagram represents a bond, each bond is two shared electrons.

Carbon chains form the structural “skeletons” of most organic molecules.

Hydrocarbons Organic molecules which consist of only carbon and hydrogen. They are the major components of petroleum, which is called fossil fuel because it consists of the decomposed remains of organisms the lived millions of years ago.

Lipids Fats, oils and waxes Serve as energy storage in animals Composed of long hydrocarbon tails attached to another molecule Nonpolar substance- will not dissolve in water

Cell Membrane Composed of two layers of phospholipids -phosphate attached to a two hydrocarbon chains

Hydrophobic Nonpolar substances “Water fearing” Repels water

Isomers Compounds that have the same numbers of atoms of the same elements but different structures and different properties.

Structural Isomers Differ in the covalent arrangements of their atoms The number increases as the carbon skeletons increase in size.

Geometric Isomers Have the same covalent partnerships but they differ in their spatial arrangements.

Enantiomers Molecules that are mirror images of each other.

L-dopa and D-dopa Enantiomers of dopamine, L-dopa is used to treat Parkinson’s disease while D-dopa is ineffective. Click picture for video

Thalidomide A medicine used to treat morning sickness in pregnant women during the 1950’s and 60’s which was a mixture of enantiomers. One of which caused severe birth defects.