Making Energy without the use of Oxygen (or Anaerobic Routes of ATP Formation)

What Yogurt, Cheese, and Sore Muscles Have in Common (or Lactate Fermentation):

• Pyruvate molecules are converted to lactate.
• Certain bacteria can sour milk and make it undrinkable but other bacteria have been used commercially to produce sour cream, cheese, yogurt, and sauerkraut.
• When muscle cells are very active, they convert to producing lactate temporarily. This lactic acid causes the muscle stiffness you may feel if you have recently begun exercising after a period of time as a couch potato or the burning feeling in your muscles after a good workout. When aerobic conditions return to the muscle, the lactic acid can be converted into ATP by aerobic respiration.

The Making of Bread and Beer (or Alcoholic Fermentation): Cellular enzymes convert pyruvate to acetaldehyde, which then accepts electrons from NADH to become alcohol. Yeasts are valuable in the baking industry (carbon dioxide by-product makes dough rise) and in alcoholic beverage production.

Anaerobic Electron Transport: This pathway, is found in many bacteria. It influences the cycling of nitrogen, sulfur, and other elements. Electrons are stripped from an organic compound and passed to inorganic elements (acceptors).

This animation (Audio - Important) describes fermentation.

This is a great time to take a quick field trip to Yellowstone National Park. The geysers and thermal pools are home to species of beautifully colored bacteria that utilize anaerobic electron transport pathways.

REVIEW: Under anaerobic conditions muscle cells produce
Answer lactate.