Anaerobic Respiration

• Anaerobic respiration is the series of chemical reactions in cells that break down nutrient molecules to release energy without using oxygen.
  • Anaerobic respiration releases much less energy per glucose molecule than aerobic respiration.

Equations

In yeast

• Word equation:
  • $\text{glucose} \rightarrow \text{alcohol} + \text{carbon dioxide}$
• Balanced chemical equation:
  • $C_6H_{12}O_6 \rightarrow 2C_2H_5OH + 2CO_2$

In human muscles during vigorous exercise

• Word equation:
  • $\text{glucose} \rightarrow \text{lactic acid}$

Lactic acid

• Lactic acid builds up in muscles and blood during vigorous exercise causing an oxygen debt.
  • High concentrations of lactic acid can cause muscle fatigue and cramps.
• This lactic acid build up creates an oxygen debt. This is the extra volume of oxygen required by the body after exercise to completely break down the accumulated lactic acid.

How oxygen debt is removed after exercise

1. Continuation of a fast heart rate: Your heart continues to beat quickly after exercise to rapidly transport lactic acid via the bloodstream away from your muscles and carry ti to the liver.
2. Continuation of deeper and faster breathing: You continue to breathe heavily to take in extra oxygen. This oxygen is absorbed into the blood and transported directly to the liver.
3. Aerobic respiration of lactic acid in the liver: Once inside the liver, the extra oxygen is used to aerobically respire the lactic acid, breaking it down safely into carbon dioxide and water.

Summary