lecture recording on 10 February 2025 at 17.14.21 PM

Introduction to Electron Transport and Glycolysis

• Electron Transport Chain: Involved in oxidative phosphorylation.

  • Receives electrons from NADH and FADH₂.

  • FADH₂ donates electrons, oxidizing to FAD.

• Energy Transfer:

  • Oxygen acts as the final electron acceptor.

  • Receives high-energy electrons to facilitate ATP production, mainly by ATP synthase (80% efficiency).

  • Allows hydrogen ions to move across the membrane, driving ATP formation crucial for cellular survival.

Overview of Glycolysis

• Glycolysis: A series of 10 chemical reactions.

  • Enzymes catalyze reactions through three phases:

    1. Initial Phase: Phosphorylation of glucose to produce glucose-6-phosphate.

       • Involves conversion of dihydroxyacetone phosphate into glyceraldehyde-3-phosphate.

    2. Middle Phase: Reductive phase where NADH is produced.

       • ATP generated through substrate-level phosphorylation.

    3. Final Phase: Production of pyruvate.

• Key Enzymes:

  • Kinases: Transfer phosphate groups (from substrates like BPG to ADP, forming ATP).

  • Dehydrogenases: Facilitate oxidation-reduction reactions, crucial for NAD+ reduction to NADH.

• Production Yield:

  • Glycolysis generates:

    • 2 ATP through substrate-level phosphorylation.

    • 2 NADH, acting as electron carriers (each NADH carries 2 electrons).

Fermentation Process

• Definition: ATP production in anaerobic conditions (absence of oxygen).

  • Regenerates NAD+ from NADH to maintain glycolysis.

  • Not limited to glycolysis but also occurs during fermentation.

  • Focus on regenerating two molecules of NAD+.

Summary

• Importance of Glycolysis and Fermentation:

  • Crucial metabolic pathways for ATP production in both aerobic and anaerobic environments.

  • Understanding enzymatic reactions and overall electron transfer mechanisms is vital for grasping cellular respiration.