Fermantation

FERMENTATION

• is the breakdown of pyruvic acid without the use of oxygen
• no ATP produced
• alcoholic and lactic acid

Alcoholic Fermentation
          - occurs in plant cells and some one-celled organisms (yeasts)
pyruvic acid + NADH + H ----------> CH3CH2OH + CO2 + NAD (returns to glycolysis)


Lactic Acid Fermentation
          - takes place when there is a short supply of oxygen in cells
pyruvic acid + NADH + H ----------> Lactic Acid + NAD (reused in glycolysis)


AEROBIC RESPIRATION

• large amount of energy is released from a glucose molecule
• takes place in the matrix and cristae (mitochondrion)
• occurs as a series of chemical reaction in which oxygen is used to convert the chemical energy stored in a organic food molecule to ATP and reduced H2 acceptor
• has 3 stages :

                                 - conversion of pyruvic acid to acetyl-CoA
                                 - Krebs cycle or Citric Acid Cycle
                                 - electron transport chain

1. Conversion of Acetyl-CoA
          - happens instead of lactic acid fermentation when you have enough oxygen
P.A. + CoA + NAD ----------> Acetyl-CoA + CO2 + NADH  + H
          1 glucose molecule = 2 molecules of Acetyl-CoA
          1 glucose molecule = 2 Pyruvic acid
                 1pyruvic acid  = 1 Acetyl-CoA


2. Krebs Cycle
          - From Sir Hans Adolf Krebs
          - The central biochemical pathway of aerobic respiration
          - Also called citric acid  cycle
          - Occurs in the inner matrix of the mitochondrion
          - Consists of :
                    - Dehydration (removal of water)
                    - Hydration (addition of water)
                    - Decarboxylation (removal of carbon dioxide)
                    - Dehydrogenation (removal of hydrogen)


3. Electron Transport Chain
         - oxidative phosphorylation
         - The breakdown of glucose is complete
         - 4 new ATP molecules are made
         - involves cytochromes (class of proteins that fuctions as electron transporter)
         - water is a by-product