Carbon and the Molecular Diversity of Life Chapter 4 Campbell and Reece 6 th Edition

Organic Chemistry The study of organic compounds is called organic chemistry. A cell is composed primarily of: –70-95% H 2 O –C,N,O,S,P A Swedish chemist in the 19 th century Jons Jakob Brazelius was the first to notice that organic compounds are found in living organisms and inorganic substances are found in the non-living. Scientists believed that is was impossible to make complex organic compounds from inorganic compounds. –Vitalism – the idea that the life force was governed by something other that chemical and physical laws. In 1828 a German chemist Fredrich Wohler attempted to make an inorganic salt called ammonium cyanate from inorganic substances but instead made urea which is present in animal urine. Other scientists were not convinced because he extracted the cyanate from living tissue. Eventually Hermann Kolbe, a student of Wohler’s was able to make acetic acid from strictly inorganic substances.

Stanley Miller In 1953 Miller used a laboratory simulation to create primitive Earth. In 1953 Miller used a laboratory simulation to create primitive Earth. Produced organic molecules in the laboratory using gases present in the primordial atmosphere like Produced organic molecules in the laboratory using gases present in the primordial atmosphere like NH 3, H 2 O, H 2 and CH 4 and electricity which simulated lightning. NH 3, H 2 O, H 2 and CH 4 and electricity which simulated lightning.

CARBON Carbon is very versatile because has a 4 valence electrons. It has a tendency to created complex branched molecules. Contributes to the diversity of organic compounds. Hydrocarbons are: –composed of hydrogen and carbon. –excellent fuels because the covalent bond between the carbon and hydrogen contain a lot of energy. –composed of partially decomposed organisms. –Hydrophobic because they are long chains of carbon bound to hydrogen atoms.

Carbon to form many different chemical compounds: Carbon to form many different chemical compounds: 1). Length of the carbon skeleton may differ ( C-C, C-C-C, C-C-C-C-C, etc.). 2). Branching of the carbon skeleton ( C-C-C-C, C-C-C-C-C ) | C

3). The number of double bonds may differ ( C=C-C-C, C=C=C-C ). 4). The molecular structure may be in ring form. Isomer - A chemical compound with the same molecular formula but a different structural formula.

Parts of Hydrocarbons are Found in Living Organisms

Organic Valences

Types of Isomers Structural –Same molecular formula but different shape. Geometric –Involves a double bond in which the groups of atoms that are covalently bound to the carbon backbone have a different spatial arrangement. Rhodopsin is a light induced isomer involved in vision. Enantiomers –Mirror images of each other Thalidimide, L-Dopa and D-Dopa

Isomers

Functional Groups Molecular groups attached to the carbon skeleton affect the function of the molecule. –Hydroxyl –Carbonyl –Carboxyl –Amino –Sulfhydryl (Thiol) –Phosphate

Estrogen Versus Testosterone a Subtle Difference in Function Groups

Estrogen and Testosterone