Carbon and the Molecular Diversity of Life
Lecture Outline
Overview: Carbon – The Backbone of Biological Molecules
* Although cells are 70–95% water, the rest consists mostly of carbon-based compounds. * Carbon is unparalleled in its ability to form large, complex, and diverse molecules. * 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). (CHONPS)
Concept 4.1 Organic chemistry is the study of carbon compounds
* The study of carbon compounds, organic chemistry, deals with any compound with carbon (organic compounds). * Organic compounds can range from simple molecules, such as CO2 or CH4, to complex molecules such as proteins, which may weigh more than 100,000 daltons. * 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 distinguish even between individuals of a single 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. * The Swedish chemist Jons Jacob Berzelius was the first to make a distinction between organic compounds that seemed to arise only in living organisms and inorganic compounds that were found in the nonliving world. * This led early organic