3. Fermentation Fermentation is a reaction that eukaryotic and prokaryotic cells use to obtain energy from food when oxygen levels are low. Fermentation is a reaction that eukaryotic and prokaryotic cells use to obtain energy from food when oxygen levels are low. Fermentation Takes energy from pyruvate in the absence of oxygen Takes energy from pyruvate in the absence of oxygen

4. Fermentation There are two types of fermentation There are two types of fermentation Alcoholic fermentation Alcoholic fermentation Lactic acid fermentation Lactic acid fermentation Both types produce 2 ATP molecules from each molecule of glucose. Both types produce 2 ATP molecules from each molecule of glucose.

5. Glucose C 6 H 12 O 6 Step 1: Glycolysis Where? In cytoplasm Where? In cytoplasm What happens? What happens? A) Glucose (from our food) is broken down into 2 pyruvate (2 - 3 carbon molecules) B) 2 ATP molecules released for cellular processes C C C ATP Mitochondrion En- zyme C C C

6. What’s after Glycolysis? Glycolysis Glycolysis Creates: 2 ATP & 2 Pyruvate (2 - 3 carbon molecules) Creates: 2 ATP & 2 Pyruvate (2 - 3 carbon molecules) Leads to either: Leads to either: 1) Aerobic Respiration With oxygen present With oxygen present Kreb’s Cycle Kreb’s Cycle Electron transport chain Electron transport chain 2) Anaerobic Respiration Without oxygen Without oxygen Fermentation Fermentation Allows glycolysis to restart Allows glycolysis to restart O2 No O 2 glycolysis fermentation ATP

7. Step 2: Fermentation Two Types of Fermentation (both anaerobic): Two Types of Fermentation (both anaerobic): A) Lactic Acid fermentation Performed by animals when muscle cells are not receiving O 2 Performed by animals when muscle cells are not receiving O 2 Lactic acid waste created Lactic acid waste created B) Alcoholic fermentation Performed by yeast, some plants, bacteria Performed by yeast, some plants, bacteria Alcohol and CO 2 waste created Alcohol and CO 2 waste created During prolonged exercise, the oxygen you inhale mainly goes to your brain. Your muscles are now lacking oxygen. Muscle cells perform fermentation to keep you going! How to relieve sore muscles: 1)Massage 2)Bananas 3)Stretch after 4)Hydrate Yeast perform alcoholic fermentation to make bread. Why isn’t bread alcoholic? Alcohol evaporates in the baking process

8. Lactic Acid vs. Alcoholic Fermentation Lactic Acid Location: Cytoplasm Location: Cytoplasm Amount of ATP created: Zero Amount of ATP created: Zero The Point? Make molecules to restart glycolysis The Point? Make molecules to restart glycolysis Waste: Lactic acid Waste: Lactic acid Alcoholic Location: Cytoplasm Location: Cytoplasm Amount of ATP created: Zero Amount of ATP created: Zero The Point? Make molecules to restart glycolysis The Point? Make molecules to restart glycolysis Waste: Alcohol and CO 2 Waste: Alcohol and CO 2 glycolysis Lactic acid fermentation Alcoholic fermentation Lactic acid Alcohol + CO 2

9. Fermentation provides cells, such as muscle cells, with energy when oxygen levels are low.

10. Glycolysis Where? In the cytoplasm What happens? Glucose is split into 2 Pyruvate (2 - 3 carbon molecules) 2 ATP created Fermentation Where? In the cytoplasm What happens? Pyruvate (2 - 3 carbon molecules) are broken into either lactic acid or alcohol Molecules to restart glycolysis created (No ATP) Aerobic Respiration Where? In the mitochondria Steps? Kreb’s cycle and electron transport chain What happens? 2 Pyruvate (2 - 3 carbon molecules) create up to 36 ATPs With oxygen present If oxygen is lacking Glycolysis restarts

11. Review 1) Name the two types of fermentation. 2) How much ATP does glycolysis create? 3) How much ATP does fermentation create? 4) Which molecule is broken down during glycolysis? 5) A buildup of which molecule causes sore muscles? 6) Which waste molecules are created by alcoholic fermentation? 7) Which waste molecules are created by lactic acid fermentation? 8) Is fermentation aerobic or anaerobic? What does this mean? 9) Why is aerobic respiration preferred vs. fermentation?