Lecture Notes: ATP and Aerobic Cellular Respiration

Introduction

• Cells are constantly active, needing energy in the form of ATP (adenosine triphosphate).
• ATP is a nucleic acid with three phosphates, essential for cell processes.
• Both prokaryotic and eukaryotic cells make ATP, although the process can vary.

Aerobic Cellular Respiration in Eukaryotic Cells

• Focus on eukaryotic cells, which have organelles like a nucleus and mitochondria.
• Mitochondria play a critical role in aerobic respiration.
• Goal: Convert glucose into ATP.

Comparison to Photosynthesis

• Photosynthesis produces glucose, while cellular respiration breaks it down to make ATP.
• Plants can perform both processes, while non-photosynthetic organisms rely on food sources for glucose.

Steps of Aerobic Cellular Respiration

Step 1: Glycolysis

• Occurs in the cytoplasm, anaerobic (does not require oxygen).
• Converts glucose into pyruvate.
• Produces net yield of 2 ATP, 2 NADH, and 2 pyruvate.

Intermediate Step

• Transport of pyruvate to the mitochondrial matrix.
• Pyruvate is oxidized to acetyl CoA.
• Release of CO2 and production of 2 NADH.

Step 2: Krebs Cycle (Citric Acid Cycle)

• Takes place in the mitochondrial matrix, considered aerobic.
• Produces 2 ATP, 6 NADH, and 2 FADH2.
• Releases CO2.

Step 3: Electron Transport Chain and Chemiosmosis

• Located in the inner mitochondrial membrane.
• Requires oxygen.
• Electrons from NADH and FADH2 create a proton gradient.
• ATP synthase uses the gradient to convert ADP into ATP.
• Oxygen acts as the final electron acceptor to form water.
• Produces a significant amount of ATP, with estimates ranging from 26-34 ATP per glucose molecule.

Total ATP Production

• Total ATP can range from 30-38 molecules per glucose, depending on various factors.

Alternative ATP Production: Fermentation

• Occurs when oxygen is not available.
• Less efficient than aerobic respiration.

Importance of ATP Production

• ATP is essential for cellular functions.
• Poisons like cyanide can disrupt ATP production by affecting the electron transport chain.
• Increased research on mitochondrial diseases due to their role in ATP production.

Conclusion

• Understanding cellular respiration and ATP production is vital for studying cellular functions and diseases.
• Encouragement to continue exploring and asking questions about cellular biology.