Lecture Notes on Aerobic Cellular Respiration

Introduction

• Discussion on morning routines and energy levels.
• Cells constantly perform processes and require energy, unlike humans who need coffee.
• ATP (Adenosine Triphosphate):
  • Nucleic acid with three phosphates.
  • Functions as the energy currency for cells.

Importance of ATP

• All cells, prokaryotic and eukaryotic, need to produce ATP.
• Aerobic Cellular Respiration: Focus on eukaryotic cells.
  • Involves membrane-bound organelles like the nucleus and mitochondria.
  • Occurs in protists, fungi, animals, and plant cells.

Process Overview

• Goal: To make ATP.
• Equation for Aerobic Cellular Respiration:
  • Inputs on the left and outputs on the right.
  • Similar to photosynthesis but not opposite.

Photosynthesis vs Cellular Respiration

• Photosynthesis produces glucose.
• Cellular respiration breaks down glucose to make ATP.
• Example: Seed germination involves cellular respiration using stored glucose.

Steps of Aerobic Cellular Respiration

Step 1: Glycolysis

• Location: Cytoplasm.
• Anaerobic process (does not require oxygen).
• Converts glucose to pyruvate.
• Net yield: 2 Pyruvate, 2 ATP, and 2 NADH.

Intermediate Step

• Pyruvate is oxidized to Acetyl CoA in the mitochondrial matrix.
• Release of carbon dioxide and production of 2 NADH.

Step 2: Krebs Cycle (Citric Acid Cycle)

• Location: Mitochondrial matrix.
• Considered aerobic as it needs oxygen indirectly.
• Acetyl CoA enters the cycle.
• Produces: 2 ATP, 6 NADH, and 2 FADH.

Step 3: Electron Transport Chain and Chemiosmosis

• Location: Inner mitochondrial membrane.
• Oxygen is required.
• NADH and FADH transfer electrons to protein complexes.
• Proton gradient is generated, allowing ATP synthase to produce ATP.
• Oxygen combines with hydrogen to form water.
• Estimated ATP yield: 26 to 34 ATP in this step; 30 to 38 ATP total per glucose molecule.

Alternative ATP Production

• Fermentation: Occurs without oxygen, less efficient than aerobic respiration.

Importance of Studying ATP Production

• Cyanide blocks ATP production; highlights the importance of ATP.
• Research on mitochondrial diseases related to ATP production is ongoing.