4.6 Fermentation KEY CONCEPT Fermentation allows the production of a small amount of ATP without oxygen. 4.6 Fermentation Objectives • Describe the process of fermentation. • Summarize the importance of fermentation. 4.6 Fermentation Vocabulary • Fermentation – Anaerobic process by which ATP is produced by glycolysis. • Lactic Acid – Product of fermentation in many types of cells, including human muscle cells. 4.6 Fermentation Fermentation allows glycolysis to continue. • Fermentation allows glycolysis to continue making ATP when oxygen is unavailable. • Fermentation is an anaerobic process. – occurs when oxygen is not available for cellular respiration – does not produce ATP 4.6 Fermentation • Fermentation allows glycolysis to continue making ATP when oxygen is unavailable. • NAD+ is recycled to glycolysis • Lactic acid fermentation occurs in muscle cells. – glycolysis splits glucose into two pyruvate molecules – pyruvate and NADH enter fermentation – energy from NADH converts pyruvate into lactic acid – NADH is changed back into NAD+ 4.6 Fermentation Fermentation and its products are important in several ways. • Alcoholic fermentation is similar to lactic acid fermentation. – glycolysis splits glucose and the products enter fermentation – energy from NADH is used to split pyruvate into an alcohol and carbon dioxide – NADH is changed back into NAD+ – NAD+ is recycled to glycolysis 4.6 Fermentation • Fermentation is used in food production. – yogurt – cheese – bread 4.6 Fermentation Question/Answer • How do long-distance runners, such as marathoners, provide the energy their bodies need for a race? – By carb-loading, eating carbohydrate-rich foods. • What has happened to a runner who “hits the wall”? – The carbohydrates are depleted. The body now burns more fat, which requires more oxygen, energy, and time to burn. - “Hitting the wall” means a runner is making ATP through glycolysis and fermentation. • Which process must happen first, fermentation or glycolysis? Explain. – Glycolysis must occur first because fermentation require pyruvate and NADH. 4.6 Fermentation Question/Answer • How are alcoholic fermentation and lactic acid fermentation similar? – They both begin with glycolysis of glucose and produce ATP and NAD+ • How are the different? – Lactic acid fermentation produces lactic acid; alcoholic fermentation produces alcohol and carbon dioxide. • Explain the importance of alcoholic fermentation in the production of bread’s light, fluffy texture. – Carbon dioxide produced from alcoholic fermentation creates gas pockets in the bread, which cause the bread to rise.