(Harvesting Chemical Energy) Glycolysis Fermentation Aerobic respiration

 Glycolysis animation  hill.com/sites/ /student_vie w0/chapter25/animation__how_glyco lysis_works.html hill.com/sites/ /student_vie w0/chapter25/animation__how_glyco lysis_works.html  Redox Reaction  Oxidation: loss of e - (glucose)  Reduced: Gain of e - (Co 2 )

 Takes place in the cytosol  1, 6 carbon molecule of glucose goes through a series of chemical reactions catalyzed by specific enzymes to produce 2, 3 carbon molecules of pyruvic acid.  NAD + similar to NADP +  NAD + carry electrons and Hydrogen ions (NADH)

 1 Glucose2 Pyruvic acid  2 ATP 4 ATP  2 NAD + 2 NADH  4 ADP + 2Phospates  Net 2 ATP

Organic Compound Glycolysis ATP no oxygenoxygen FermentationAerobic Respiration

 Prokaryotes and protists in anaerobic habitats (mainly unicellular organisms)  Does not produce ATP  Many Fermentation pathways differ in the types of enzymes and final products produced  Two most common produced are lactic acid and ethyl alcohol

 Occurs in muscle cell when strenuous exercise causes muscle cells to use up all the oxygen available to them. They switch to anaerobic respiration and lactic acid builds up in the cells, changing the acidity of the cytoplasm.  Increased acidity decreases the cells ability to contract causing cramps and fatigue.  Eventually it diffuses out of cell into blood stream and is transported to liver where it is converted back into pyruvic acid.  Used to make cheese and yogurt

 Used by some plants and unicellular organisms such a yeast  Bread making

 e/animations/fermentation.swf e/animations/fermentation.swf

 Requires O 2  Approximately 20 times as much ATP produced then glycolysis  Two major stages: Krebs cycle and the electron transport chain  In eukaryotic cell takes place in the mitochondria.  Krebs cycle occurs in the mitochondrial matrix  Electron transport chain occurs in the inner membrane

 Pyruvic acid enters the mitochondrial matrix  It reacts with a molecule called coenzyme A (CoA) to form acetyl CoA  CO 2 and NADH and H + are produced

Step 1: Acetyl CoA combines with Oxaloacetic acid to form citric acid (regenerates CoA) Step 2: Citric acid releases CO 2 and a H atom that combines with NAD + to form NADH + H + to form 5 carbon compound. Step 3: 5 carbon compound releases CO 2 and a Hydrogen atom (combines with NAD + to form NADH + H + ) to form a 4 carbon compound. A molecule of ATP is formed.

 Step 4: 4 Carbon compound releases a hydrogen atom ( combines with FAD to Form FADH 2 ) and is converted to another 4 carbon compound.  Step 5: The 4 carbon compound releases a hydrogen atom and is (combines with NAD + to form NADH + H + )converted back into Oxaloacetic acid.

 1 glucose molecule = 2 turns of the Krebs cycle  6 NADH  2 FADH 2  2 ATP  4 CO 2

 Most of the energy from glucose still have not been transferred to ATP  10 NADH and the 2 FADH 2 produced so far to drive the electron transport chain