1. Fermentation Anaerobic Alternative to Aerobic Respiration

2. OK, if you are yeast... Making 2 ATP from glycolysis is enough

3. Only catch... NAD+ is used up So a cell needs a way to regenerate it

4. They Replenish NAD+ When yeast and bacteria convert pyruvic acid to CO 2 and ethanol (ethyl alcohol).

5. Alcoholic Fermentation “The production of ethanol from glucose” Is catalyzed by microbial (bacteria and yeast) enzymes

6. Yeast Acting on Pyruvic Acid Ethanol is released as a waste product O o o NAD+ CO 2

7. In Muscle Cells Lactic Acid Fermentation No CO 2 given off Eventually carried back to liver to be converted to pyruvic acid

8. Lactic Acid in Bacteria Used in dairy industry to make cheese and yogurt

9. Strict Anaerobes REQUIRE anaerobic (no oxygen) to live EXAMPLES: those that live in stagnant ponds and soil

10. Facultative Anaerobes Can make ATP by fermentation either by chemiosmosis or by fermentation, depending whether O 2 is present or not EXAMPLES: E. coli, yeasts

11. Why must oxygen be kept out of the wine and beer vats? If oxygen is present, the pyruvic acid will make CO2 and water. If oxygen is not present, yeast and bacteria will make ethanol and CO 2.