Redox Reactions

Learning Objectives

• Discuss importance of electrons in energy transfer in living systems.
• Explain electron transfer to carrier molecules.

Energy Production and Redox Reactions

• Energy production involves coordinated chemical pathways, mainly oxidation and reduction reactions (redox).
• Oxidation: Strips an electron from a compound.
• Reduction: Addition of electron to another compound.
• Redox reactions occur simultaneously; remember with "OIL RIG" (Oxidation Is Loss, Reduction Is Gain).

Role of Electrons in Cellular Functions

• High-energy electrons are key for energy storage and cell function.
• Electron transfer allows incremental energy usage instead of large bursts.

Electron Carriers

• Compounds act as electron shuttles, binding and carrying high-energy electrons.
• Major electron carriers:
  • NAD (Nicotinamide Adenine Dinucleotide):
  • Derived from vitamin B3, niacin.
  • NAD+ (oxidized) and NADH (reduced) after accepting electrons and a proton.
  • "H" indicates reduction (e.g., NADH is reduced form).
  • FAD (Flavin Adenine Dinucleotide):
  • Derived from vitamin B2, riboflavin.
  • FAD+ (oxidized) and FADH2 (reduced).
  • NADP (Nicotinamide Adenine Dinucleotide Phosphate):
  • Variation of NAD with an additional phosphate.
  • Important in photosynthesis.

Cellular Respiration and ATP Production

• A key metabolic process; tracks electron transfers through pathways.
• NADH produced indicates oxidation of food molecules.
• Electrons from NADH are used in the electron transport chain to synthesize ATP.