Lecture Notes on Cellular Respiration and ATP Production

Introduction

• Discussion on morning routines and energy levels.
• Cells require constant energy, supplied by ATP (Adenosine Triphosphate).
• ATP: a nucleic acid with three phosphates, serving as an energy currency for cells.

ATP Production

• ATP production is essential for all cells (prokaryotes and eukaryotes).
• Processes can differ between cell types.

Aerobic Cellular Respiration

• Focus on aerobic cellular respiration in eukaryotic cells.
• Eukaryotic Cells: Cells with membrane-bound organelles (nucleus, mitochondria).
• Involves cells from protists, fungi, animals, and plants.
• Major goal: Produce ATP.

Aerobic Cellular Respiration Equation

• Reactants (inputs) on the left, products (outputs) on the right.
• Similar to photosynthesis, but not opposites.

Photosynthesis vs. Cellular Respiration

• Photosynthesis produces glucose, cellular respiration breaks it down.
• Example: Germinating bean uses stored glucose for cellular respiration.
• Plants: Perform both photosynthesis and cellular respiration.
• Non-photosynthetic organisms (e.g., humans, amoebas): Require external glucose sources.

Steps of Aerobic Cellular Respiration

Step #1: Glycolysis

• Occurs in the cytoplasm (anaerobic process).
• Converts glucose to pyruvate.
• Produces: 2 pyruvate, 2 ATP, 2 NADH.
• NADH: Coenzyme transferring electrons.

Intermediate Step

• Pyruvate actively transported into the mitochondria.
• Pyruvate oxidized to acetyl CoA, releases CO2, produces NADH.

Step #2: Krebs Cycle (Citric Acid Cycle)

• Occurs in the mitochondrial matrix (aerobic process).
• Produces: 2 ATP, 6 NADH, 2 FADH2, releases CO2.
• FADH2: Coenzyme assisting in electron transfer.

Step #3: Electron Transport Chain & Chemiosmosis

• Located in the inner mitochondrial membrane (requires oxygen).
• Electrons transferred from NADH and FADH2 to protein complexes.
• Proton gradient generated across the membrane.
• Protons travel via ATP synthase to produce ATP.
• Oxygen is the final electron acceptor.
• Produces water.

ATP Yield

• Varied estimates of ATP production: 26-34 ATP molecules per glucose.
• Total ATP from all steps: 30-38 ATP molecules per glucose.
• Importance of understanding range instead of fixed numbers.

Alternate Pathways

• Fermentation: ATP production without oxygen, less efficient.

Importance of ATP Production

• ATP production is crucial for cell survival.
• Cyanide blocks electron transport chain, inhibiting ATP production.
• Mitochondrial diseases and research for treatments are important.

Conclusion

• Encouragement to stay curious and explore cellular processes.

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End of Lecture Notes