Lecture Notes: Aerobic Cellular Respiration

Introduction

• Discussion on morning energy levels and need for caffeine.
• Contrasts energy needs of humans with constant energy requirements of cells.
• Key Concept: Cells require ATP (adenosine triphosphate) for energy, which is essential for active transport and other processes.

ATP (Adenosine Triphosphate)

• ATP is a nucleic acid with three phosphates.
• Known as the energy currency of the cell.

Production of ATP

• Essential for both prokaryotic and eukaryotic cells.
• Production method varies between cell types.

Aerobic Cellular Respiration in Eukaryotic Cells

• Eukaryotic Cells: Include protists, fungi, animals, and plants; characterized by membrane-bound organelles.
• Mitochondria: Central to aerobic cellular respiration.
• Overall Goal: To produce ATP.

Aerobic Cellular Respiration Equation

• Reactants (inputs) on the left side, products (outputs) on the right.
• Similar to photosynthesis, but involves breaking down glucose to generate ATP.

Photosynthesis vs. Cellular Respiration

• Photosynthesis creates glucose; cellular respiration breaks it down.
• Example: Germinating bean seeds use stored glucose via cellular respiration before they can perform photosynthesis.

Steps of Aerobic Cellular Respiration

Step 1: Glycolysis

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

Intermediate Step

• Pyruvate transported to mitochondrial matrix.
• Converted into acetyl CoA; releases CO2 and produces NADH.

Step 2: Krebs Cycle (Citric Acid Cycle)

• Takes place in mitochondrial matrix; aerobic cycle.
• Produces CO2, 2 ATP, 6 NADH, and 2 FADH2.
• FADH2: Another coenzyme for electron transfer.

Step 3: Electron Transport Chain and Chemiosmosis

• Occurs in the inner mitochondrial membrane; requires oxygen.
• Process: Electrons transferred from NADH and FADH2 to protein complexes, creating proton gradient.
• ATP Synthase: Enzyme that produces ATP using this gradient.
• Final Electron Acceptor: Oxygen, forming water (H2O).
• ATP Yield: Range from 26-34 ATP molecules per glucose molecule.

Total ATP Production

• Including all steps, estimates range from 30-38 ATP per glucose molecule.

Alternative ATP Production: Fermentation

• Occurs when oxygen is unavailable.
• Less efficient than aerobic respiration.

Importance of ATP

• Crucial for cell survival and function.
• Cyanide inhibits electron transport chain, illustrating ATP's importance.
• Research on mitochondrial diseases is ongoing and critical.

Conclusion

• Emphasizes continued research and curiosity in cellular processes.

End Reminder: Stay curious and explore further resources and references. The Amoeba Sisters encourage further learning on these topics.