Biochemical Pathways (Part Deux-The Autotrophs)
Photosynthesis
The process by which plants and some bacteria (remember cyanobacteria and
stromatolites?) use the energy from sunlight to produce organic molecules.
Sunlight energy absorbed by the chlorophyll splits H2O, with the H+
reducing the CO2 to sugar,
and the O2 given off as a gas. The shorthand equation is:
6H2O
+ 6CO2 + Light ---> C6H12O6 + 6O2
Note, this is the REVERSE of oxidation, shown previously!
Chemosynthesis
Some autotrophic microorganisms can live in the
dark and obtain energy by oxidizing inorganic chemicals. The shorthand equation
is:
6CO2 + 6H20 + Reduced
chemical (e.g. H2S, Fe2+) ---> C6H12O6 + Oxidized chemical (e.g. S, Fe3+)
Examples of this include many of the microbes
living at the deep sea vents.
So, what do you suppose is a Phototroph? How about a Chemotroph?
Does any one know what is a Lithotroph? (inorganic chem rxns) How about an Organotroph? (organic chemical rxns)
Lots of "trophs"!