Understanding Aerobic Cellular Respiration

Sep 4, 2024

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Lecture Notes: Aerobic Cellular Respiration

Introduction

  • Energy currency in cells is ATP (adenosine triphosphate).
  • ATP is a nucleic acid packed with three phosphates.
  • All cells, prokaryote or eukaryote, need to produce ATP.
  • This lecture focuses on ATP production through aerobic cellular respiration in eukaryotic cells.
  • Key organelle: Mitochondria.

Overview of Aerobic Cellular Respiration

  • Goal: To produce ATP efficiently.
  • Equation is similar to photosynthesis but involves breaking down glucose.
  • Non-photosynthetic organisms (e.g. humans) need glucose from external sources.

Steps of Aerobic Cellular Respiration

  1. Glycolysis

    • Occurs in the cytoplasm; anaerobic process.
    • Converts glucose into pyruvate.
    • Net yield: 2 pyruvate, 2 ATP, and 2 NADH.
      • NADH: Coenzyme for electron transfer.

  2. Intermediate Step

    • Pyruvate is transported into the mitochondrial matrix.
    • Pyruvate is oxidized to acetyl CoA.
    • Products: 2 acetyl CoA, carbon dioxide, and 2 NADH.

  3. Krebs Cycle (Citric Acid Cycle)

    • Occurs in the mitochondrial matrix; considered aerobic.
    • Acetyl CoA enters the cycle.
    • Products: Carbon dioxide, 2 ATP, 6 NADH, and 2 FADH.
      • FADH: Coenzyme assisting in electron transfer.

  4. Electron Transport Chain and Chemiosmosis

    • Occurs in the inner mitochondrial membrane; requires oxygen.
    • Electrons from NADH and FADH are transferred to protein complexes.
    • Creates a proton gradient that powers ATP synthase to produce ATP.
    • Oxygen acts as the final electron acceptor, forming water.
    • ATP yield varies (26 to 34 ATP per glucose molecule from this step alone).
    • Total ATP yield from all steps ranges between 30 to 38 ATP per glucose molecule.

Additional Information

  • Fermentation: Alternative ATP production in absence of oxygen, but less efficient.
  • Mitochondrial diseases: Research is ongoing to improve treatment.
  • Importance of ATP: Blockage in ATP production (e.g., by cyanide) can be deadly.

Conclusion

  • Aerobic cellular respiration is crucial for ATP production.
  • Understanding cellular processes promotes curiosity and innovation in treatment and research.

Stay curious and keep exploring the fascinating world of cellular biology!