Lecture Notes: Aerobic Cellular Respiration and ATP Production

Introduction

• Importance of ATP (Adenosine Triphosphate) as the energy currency for cells
• ATP is a nucleic acid with three phosphates
• Organisms need to produce ATP regardless of being prokaryotic or eukaryotic
• Aerobic cellular respiration in eukaryotic cells is the focus
  • Occurs in cells with membrane-bound organelles like the nucleus and mitochondria

ATP Production Process

• Goal: To produce ATP
• Aerobic Cellular Respiration Equation
  • Reactants (inputs) on the left, products (outputs) on the right
  • Similarities with photosynthesis: glucose is a shared substance

Glucose and Energy

• Glucose breakdown is essential for ATP production
• Example: Germinating bean seeds use stored glucose before photosynthesis capability
  • Plants can perform both photosynthesis and cellular respiration
• Non-photosynthetic organisms need an external glucose source

Steps of Aerobic Cellular Respiration

Step 1: Glycolysis

• Location: Cytoplasm (anaerobic process)
• Conversion of glucose to pyruvate
• Net yield: 2 pyruvate, 2 ATP, and 2 NADH
• Role of NADH: Electron transfer for later ATP production

Intermediate Step

• Pyruvate enters mitochondria matrix via active transport
• Pyruvate oxidation: conversion to acetyl CoA, releasing CO2 and producing NADH

Step 2: Krebs Cycle (Citric Acid Cycle)

• Location: Mitochondrial matrix
• Aerobic process (oxygen necessary for continuation)
• Yield: 2 ATP, 6 NADH, 2 FADH2 (coenzyme for electron transfer)

Step 3: Electron Transport Chain and Chemiosmosis

• Location: Inner mitochondrial membrane
• Requires oxygen
• Process overview: Electrons from NADH and FADH2 transferred to protein complexes, generating a proton gradient
• ATP synthase uses the proton gradient to synthesize ATP from ADP
• Oxygen as the final electron acceptor, forming water
• Yield varies: 26-34 ATP from this step alone
• Total ATP per glucose: 30-38 depending on various factors

Alternative ATP Production

• Fermentation as an anaerobic alternative when oxygen is unavailable

Importance of ATP and Mitochondrial Health

• Example: Cyanide blocks electron transport chain step, inhibiting ATP production
• Mitochondrial diseases and the need for research

Conclusion

• Continuous exploration and inquiry are necessary for advancements in cellular bioenergetics

• Stay curious and keep exploring new concepts!