Anaerobic Respiration

Anaerobic Cellular Respiration

Overview

  • Anaerobic respiration occurs without oxygen or mitochondria.

  • It consists mainly of glycolysis followed by fermentation.

Importance of Aerobic Respiration

  • Aerobic respiration involves key processes:

    • Glycolysis: Breaks glucose into pyruvate, yielding 2 ATP.

    • Kreb Cycle: Converts pyruvate to acetyl CoA, releasing CO2 and producing 2 ATP.

    • Electron Transport Chain: Uses NADH and FADH2 to produce approximately 32-34 ATP.

Causes for Anaerobic Respiration

  • Anaerobic respiration kicks in when:

    • Mitochondria are destroyed or insufficient.

    • Oxygen is unavailable, leading to electron transport chain failure.

Effects of Anaerobic Conditions

  • Holding breath demonstrates consequences of anaerobic conditions:

    • Body runs out of ATP, leading to pain and muscle fatigue due to lactic acid buildup.

Glycolysis and NADH

  • In glycolysis, glucose is broken down into pyruvate:

    • Produces 2 ATP and converts energy into NADH.

    • Accumulation of NADH leads to a bottleneck without oxygen or mitochondria.

Solutions through Fermentation

Lactic Acid Fermentation

  • Occurs in animals and some bacteria:

    • Pyruvate is converted to lactate (lactic acid).

    • NADH donates electrons to lactate, regenerating NAD+ for glycolysis.

    • Allows continuous energy production through glycolysis despite the absence of oxygen.

Alcoholic Fermentation

  • Primarily occurs in yeast:

    • Pyruvate is converted into ethyl alcohol and carbon dioxide.

    • Releases NAD+ and allows glycolysis to continue; carbon dioxide contributes to beer and wine bubbles.

Practical Examples

  • Lactic Acid Fermentation: Experienced during intense exercise, causing muscle pain from lactate buildup.

  • Alcoholic Fermentation: Used in brewing; converting sugars into ethanol and CO2 in anaerobic conditions.

Conclusion

  • Anaerobic respiration is vital in situations lacking oxygen or mitochondria, providing temporary energy through fermentation processes.

  • Its efficiency is limited compared to aerobic respiration, as it yields significantly less ATP.