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The Wonders of Photosynthesis and Cellular Respiration

Cellular Respiration (Glycolysis)

Table of Contents
Photosynthesis (Light Reactions)
Photosynthesis (Dark Reactions)
Affecting Factors of Photosynthesis
Cellular Respiration (Glycolysis)
Cellular Respiration (Aerobic Respiration)
Linking Photosynthesis to Cellular Respiration

ATP Production

   Glycolysis is a biochemical pathway in which one six-carbon molecule of glucose is oxidized to produce two three-carbon molecules of pyruvic acid.  Glycolysis is an anaerobic (oxygen not needed) series of chemical reactions that are catalyzed by specific enzymes.  Glycolysis takes place in the cytosol of the cell.

   At the beginning of the process 2 ATP are used to convert one molcule of glucose into a new six-carbon molecule with two phosphate groups attached.  This turns the two ATP into two ADP.  Next the two phosphate split the new carbon compound into two molecules of glyceraldehide 3 Phosphate (G3P).  Next up the two G3P become oxidized and they each receive a new phosphate group.  This phosphate group comes from the reduction of nicotine adenine dinucleotide (NAD+) to NADH.  Recall that there are two G3P so everything desribed at this point happens twice so there are now two NADH.  Lastly the phosphate groups break from the G3P is given to two ADP producing two ATP. There are two G3P so four ATP are produced in total.  The two G3P molecules are then converted into pyruvic acid.  For every single glucose molecule used, there is net production of two ATP. 

   What happens to the pyruvic acid depends on the type of cell and whether oxygen is present.   



   This process uses the pyruvic acid that was was produced during glycolysis.  The pyruvic acid goes through aditional biochemical pathways to which creates more NAD+. This process does not produce ATP but allows for the continuation of glycolysis.  There are many fermentation pathways which have different end results.  There are two common fermentation pathways which produce lactic acid (used in the production of cheese and other dairy products) and ethyl alcohol (yeast and bread). 
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