By: Jordan, Zach, Paige and Gabby

WHAT IS FERMENTATION? -In the absence of oxygen, some cells convert pyruvic acid into other compounds through additional biochemical pathways in the cytosol. -Glycolysis + additional pathways = fermentation -Additional fermentation does not produce ATP, but regenerate NAD+, used to keep glycolysis going to make more ATP.

WHAT IS FERMENTATION? -Many fermentation pathways and they differ in terms of enzymes used and compounds made form pyruvic acid -Two common fermentation pathways result in production of lactic acid and ethyl alcohol

-Enzyme converts pyruvic acid into 3 carbon compound (lactic acid) -Involves transfer of 2 hydrogen atoms from NADH and H+ to pyruvic acid (NADH is oxidized to form NAD+) -Regeneration of NAD+ in lactic acid fermentation helps keep glycolysis operating -LAF by microorganisms plays essential role in manufacture of food products

LACTIC ACID FERMENTATION -Lactic acid occurs in muscle cells during strenuous exercise (use up oxygen more rapidly than it can be delivered to them) -Muscle cells switch from aerobic respiration to LAF, as oxygen becomes depleted -Lactic acid built up in muscle cells makes cell’s cytosol more acidic (reduces limit to which the cells can contract) -Eventually lactic acid diffuses into blood, is transported to liver, is converted back into pyruvic acid when oxygen becomes available

-Converts pyruvic acid into ethyl alcohol in some plant cells and unicellular organisms Pathway requires 2 steps: 1. carbon dioxide molecule is removed from pyruvic acid, leaving a 2-carbo compound 2. 2 hydrogen atoms get added to the 2-carbon compound, forming ethyl alcohol

ALCOHOLIC FERMENTATION - Like in LAF, hydrogen atoms come from NADH and H+, regenerating NAD+ for use in glycolysis - The basis for wine and beer industries. Yeast cells added top fermentation mixture, providing enzymes needed for AF - As fermentation proceeds, ethyl alcohol accumulates in the mixture until it reaches a concentration that inhibits fermentation.

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