Chapter 4 Carbon and the Molecular Diversity of Life

Organic Chemistry  Organic chemistry is the study of carbon containing compounds. These compounds must also contain hydrogen to be considered organic.  CO 2, CO, and CaCO 3, etc., for example, are not considered organic despite the fact that they contain carbon. The reason being, there is no hydrogen.  Organic chemistry is the study of carbon containing compounds. These compounds must also contain hydrogen to be considered organic.  CO 2, CO, and CaCO 3, etc., for example, are not considered organic despite the fact that they contain carbon. The reason being, there is no hydrogen.

Organic Chemistry and Vitalism  Organic chemistry was originally built on the idea of vitalism--the idea that there was a life force outside of the laws of physics and chemistry.  Thus, the belief was that organic molecules could only be synthesized by living organisms.  Organic chemistry was originally built on the idea of vitalism--the idea that there was a life force outside of the laws of physics and chemistry.  Thus, the belief was that organic molecules could only be synthesized by living organisms.

Organic Chemistry and Vitalism  In 1828, Frederick Wöhler set out to synthesize ammonium cyanate by mixing NH 4 + and CNO -. Instead of getting ammonium cyanate, they synthesized urea--a product once thought to only be produced by humans and animals.

Organic Chemistry and Vitalism  Because the cyanate had been extracted from animal blood, Wöhler’s idea didn’t get much credit until one of his students synthesized organic acetic acid from products obtained from pure elements.

Vitalism Vs. Mechanism  Eventually, the idea of vitalism shifted to mechanism which is the view that life and other natural phenomena are governed by physical and chemical laws.

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Carbon and Bonding  What makes carbon so unique is the ability to bond 4 times because it has 4 valence shell electrons.  The majority of the time, carbon forms covalent bonds.  There are many different types of bonds carbon can form.  What makes carbon so unique is the ability to bond 4 times because it has 4 valence shell electrons.  The majority of the time, carbon forms covalent bonds.  There are many different types of bonds carbon can form.

Carbon and Bonding  Carbon can form a single bond with 4 atoms as in the case for methane, CH 4.  It can form one or more double bonds as in the case of CO 2, C 2 H 4, CO(NH 2 ) 2, or carbon dioxide, ethene, and urea respectively.  Carbon can also form triple bonds as seen in acetylene, C 2 H 2, carbon monoxide, CO.  Carbon can form a single bond with 4 atoms as in the case for methane, CH 4.  It can form one or more double bonds as in the case of CO 2, C 2 H 4, CO(NH 2 ) 2, or carbon dioxide, ethene, and urea respectively.  Carbon can also form triple bonds as seen in acetylene, C 2 H 2, carbon monoxide, CO.

Carbon and Bonding  Carbon also has the ability to form long chains, some of which contain double bonds.  Butene, C 4 H 10  Carbon can also form ring structures as seen in benzene, C 6 H 6.  Carbon also has the ability to form long chains, some of which contain double bonds.  Butene, C 4 H 10  Carbon can also form ring structures as seen in benzene, C 6 H 6.

Carbon and Bonding  Additionally, ball shaped carbon containing compounds called “buckeyballs” they are C-60 and are called buckeyballs.

Carbon and Bonding  The diversity of carbon allows a nearly endless supply of compounds to be made, and it is this reason that carbon plays such a large and important role in biology.

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Hydrocarbons  Hydrocarbons are compounds consisting of only hydrogen and carbon. They serve as a basis for petroleum, while not common in living organisms, many organic molecules in a cell consist of a region containing only H and C.

Hydrocarbons  For example, long chain fatty acids contain a region consisting of hydrogen and oxygen and attached to this is a long chain of carbon and hydrogen atoms.  The oxygen and hydrogen regions are hydrophilic and the carbon-hydrogen regions are hydrophobic. This will serves as an important point later when we discuss cell membranes.  For example, long chain fatty acids contain a region consisting of hydrogen and oxygen and attached to this is a long chain of carbon and hydrogen atoms.  The oxygen and hydrogen regions are hydrophilic and the carbon-hydrogen regions are hydrophobic. This will serves as an important point later when we discuss cell membranes.