Lecture Notes: Bioenergetics and Redox Reactions

Introduction

• Presenter: Andy from Med School EU
• Topic: Bioenergetics, specifically redox reactions in living organisms

Redox Reactions Overview

• Definition: Energy capturing and releasing processes involving oxidation and reduction reactions.
• Key Concept: Transfer of electrons is fundamental to redox reactions.
  • Coupled with the transfer of protons to balance energy.
• Oxidation: Loss of electrons
• Reduction: Gain of electrons
• Redox reactions are important in processes like glycolysis and other energy metabolizing processes.

Oxidation Levels of Carbon Compounds

• Concept: More oxygen atoms imply higher oxidation levels.
• Examples of Oxidation States:
  • Methane (CH4): Fully saturated, reduced state.
  • Alkane (CH3): Less saturated, more oxidized.
  • Aldehyde/Ketone: Higher oxidation level with double bond to oxygen.
  • Carboxyl Group: Highest oxidation level with no bonds to hydrogen.
• Trend: More oxygen and fewer hydrogen bonds = more oxidized.

Practical Examples of Redox Reactions

NAD+ to NADH Conversion

• Reaction: AH2 transfers electrons and a proton to NAD+.
• Outcome:
  • NAD+: Reduced to NADH (gains electrons)
  • AH2: Oxidized (loses electrons)

Step 6 of Glycolysis

• Reaction: Glyceraldehyde 3-phosphate undergoes redox reaction.
• Process:
  • Addition of inorganic phosphate (Pi) results in 1,3-bisphosphoglycerate.
  • NAD+ is reduced to NADH (gains electrons and a hydrogen ion).
  • Glyceraldehyde 3-phosphate: Oxidized.

Cellular Respiration

• Overall Reaction:
  • Glucose (C6H12O6): Oxidized, loses electrons and oxygen.
  • Oxygen (O2): Reduced.

Conclusion

• Redox reactions are essential in biological systems, especially in energy metabolism.
• Future topics include photosynthesis and cellular respiration which involve numerous redox reactions.

Next Steps

• Upcoming videos will cover the photosynthesis process and its associated reactions.