Carbon and the Molecular Diversity of Life
A. Carbon—The Backbone of Biological Molecules
Although cells are 70–95% water, the rest consists mostly of carbon-based
Carbon is unparalleled in its ability to form large, complex, and diverse
Carbon accounts for the diversity of biological molecules and has made
possible the great diversity of living things.
Proteins, DNA, carbohydrates, and other molecules that distinguish living
matter from inorganic material are all composed of carbon atoms bonded to each
other and to atoms of other elements.
These other elements commonly include hydrogen (H), oxygen (O), nitrogen
(N), sulfur (S), and phosphorus (P).
1. Organic chemistry is the study of carbon compounds.
The study of carbon compounds,
deals with any
compound with carbon (organic compounds).
Organic compounds can range from simple molecules, such as CO
to complex molecules such as proteins, which may weigh more than 100,000
The overall percentages of the major elements of life (C, H, O, N, S, and P)
are quite uniform from one organism to another.
However, because of carbon’s versatility, these few elements can be
combined to build an inexhaustible variety of organic molecules.
Variations in organic molecules can even account for differences among
individuals of the same species.
The science of organic chemistry began in attempts to purify and improve the
yield of products obtained from other organisms.
Initially, chemists learned to synthesize simple compounds in the laboratory,
but had no success with more complex compounds.