Anaerobic Respiration

Anaerobic Respiration - Fundamentals

  • Anaerobic respiration is the process in which energy is produced by the breakdown of glucose in the absence of oxygen.
  • This type of respiration is termed anaerobic, meaning ‘without air’, due to the lack of oxygen involvement.
  • There are two types of anaerobic respiration: alcoholic fermentation and lactic acid fermentation.
  • The general equation for anaerobic respiration in animal cells is: C6H12O6(glucose) → 2C3H6O3(lactic acid) + energy
  • In yeast cells, alcoholic fermentation is performed and the equation is: C6H12O6(glucose) → 2C2H5OH(ethanol) + 2CO2(carbon dioxide) + energy
  • The energy produced in anaerobic respiration is less compared to aerobic respiration.

Where does Anaerobic Respiration occur?

  • Anaerobic respiration primarily takes place in the cytoplasm of cells when insufficient oxygen is available.
  • It is common in muscles during intense exercise, where oxygen supply can’t meet the demand, and in certain microorganisms like yeast.

Stages of Anaerobic Respiration

  • Anaerobic respiration consists of two stages: glycolysis and either lactic acid fermentation or alcoholic fermentation depending on the organism involved.

  • Glycolysis: This step is the same as in aerobic respiration where one glucose molecule gets converted into two pyruvate molecules and releases 2 ATPs.

  • In lactic acid fermentation in humans, pyruvate is converted to lactic acid, which can cause muscle fatigue.

  • In alcoholic fermentation in yeast, pyruvate is converted into ethanol and carbon dioxide, used commercially for brewing and baking.

Importance of Anaerobic Respiration

  • Energy production: Even though less efficient compared to aerobic respiration, anaerobic respiration allows organisms to generate energy when oxygen is scarce.
  • Survival mechanism: It’s a strategy employed by some organisms in oxygen-deprived environments or during intense physical activity.

Anaerobic vs Aerobic Respiration

  • In contrast to aerobic respiration, anaerobic respiration doesn’t fully break down glucose, thus producing less energy.
  • However, it has the advantage of being able to function without oxygen and it’s faster than aerobic respiration.
  • The end products differ, with anaerobic respiration producing lactic acid or ethanol, depending on the organism, instead of carbon dioxide and water.