General ---------Biology ------------------Online--------------------------wilcox@sunline.net Ch.  2 :  The Chemical Context of Life

I have selected methane because it is the simplest "organic" molecule.

On the previous two pages we combined "subatomic particles" to form atoms.  Now we are going to combine four atoms of hydrogen with one atom of carbon and make a molecule called methane.

Methane

Chemical Formula	Structural Formula
CH4

Here is a summary list of stuff about methane and other organic molecules.  The most common source of naturally occurring methane is the breakdown of organic molecules during digestion and respiration.  There is a lot of methane in a fart.

• A methane molecule is assembled by combining 4 hydrogen and a carbon.
• This requires a chemical reaction.
• Carbon and hydrogen will not spontaneously combine. 
• It takes energy to combine these atoms.
• Once combined, the 5 atoms are held together by 4 "chemical bonds"  called "covalent bonds."  ("Co" means together & "valent" means the outer or valence electrons)
• In the glucose molecule, the bonds are shown as short lines.
• Some of the energy used to combine the atoms is stored in the chemical bonds.
• The bond is a covalent bond and results from sharing electrons
• Methane is a gas, it burns easily.
• The heat given off during burning comes from the bonds that held the atoms together

• the four lines represent four covalent bonds (shared electrons)
• the bond are where the chemical energy is stored in the molecule
• organic molecules are usually derived from sugar produced during photosynthesis
• photosynthesis uses energy from the sun to combine the atoms of C,H,O together in the sugar
• the stored energy in these covalent bonds is the energy you get from food