Lecture on Cellular Respiration and ATP Production

Introduction

• Discussion on morning routines and energy levels.
• Cells constantly perform processes like active transport, requiring energy.
• ATP (Adenosine Triphosphate): Primary energy currency in cells.

ATP Production in Cells

• All cells (prokaryotic and eukaryotic) must produce ATP.
• Aerobic Cellular Respiration: Process focused on in this lecture for eukaryotic cells.
  • Involves mitochondria.
• Equation: Reactants on the left, products on the right. Parallels with photosynthesis noted.

Steps of Aerobic Cellular Respiration

Step 1: Glycolysis

• Location: Cytoplasm (anaerobic process).
• Conversion: Glucose to pyruvate.
• Yield:
  • 2 Pyruvate
  • 2 ATP
  • 2 NADH (electron transfer coenzyme)

Intermediate Step

• Transport of pyruvate to mitochondria.
• Conversion: Pyruvate to Acetyl CoA.
• Output: CO2 and 2 NADH.

Step 2: Krebs Cycle (Citric Acid Cycle)

• Location: Mitochondrial matrix.
• Considered aerobic.
• Yield:
  • 2 ATP
  • 6 NADH
  • 2 FADH2 (another electron transfer coenzyme)
• CO2 released.

Step 3: Electron Transport Chain and Chemiosmosis

• Location: Inner mitochondrial membrane.
• Requires oxygen.
• Process:
  • Electrons transferred from NADH and FADH2.
  • Proton gradient created, powering ATP synthase.
  • Oxygen as the final electron acceptor, forming water.

ATP Yield

• Variation in ATP yield due to multiple factors.
• Estimated range: 26-34 ATP (electron transport) + 4 ATP (glycolysis and Krebs) = 30-38 ATP total per glucose molecule.

Alternative Pathways

• Fermentation: Process for ATP production without oxygen.
• Potentially less efficient than aerobic respiration.

Importance of ATP and Mitochondria

• Cyanide can inhibit electron transport chain, highlighting ATP's importance.
• Mitochondrial diseases and research.

Conclusion

• Encouragement to stay curious about cellular processes.