Lecture Notes: Bioenergetics

Introduction

• Speaker: Andy from Med School EU
• Topic: Bioenergetics
• Focus: Energy currency of cells - ATP (Adenosine Triphosphate)

ATP: Structure and Components

• ATP Components:
  • Adenosine group
  • Three phosphates
• Adenosine:
  • Contains a nitrogenous base: Adenine
  • Five-carbon sugar
• Nucleoside vs Nucleotide:
  • Nucleoside: Adenine + five-carbon sugar
  • Nucleotide: Nitrogenous base + phosphate
  • ATP vs Nucleotide: ATP has three phosphates

Chemical Bonds in ATP

• Ester Bonds:
  • Between carbon, oxygen, and phosphate
  • Releases 14.2 kJ/mol upon hydrolysis
• Anhydride Bonds:
  • Between phosphate groups
  • Specifically, phospho-anhydride bonds
  • Release more energy than ester bonds:
    • 30.5 kJ/mol
    • 32.8 kJ/mol

Hydrolysis of ATP

• Phosphate Labels:
  • Alpha, Beta, and Gamma phosphates
• Hydrolysis Products:
  • ATP to ADP:
    • Release one phosphate (gamma phosphate)
    • Products: ADP (Adenosine Diphosphate) + Inorganic Phosphate (Pi)
    • Common in glycolysis
  • ATP to AMP:
    • Hydrolysis at beta phosphate
    • Products: AMP (Adenosine Monophosphate) + Pyrophosphate
    • Pyrophosphate can hydrolyze further to two inorganic phosphates

Importance of ATP

• Energy Release: Hydrolysis of anhydride bonds provides necessary energy for cellular reactions.
• Applications:
  • Glycolysis and other biochemical reactions

Conclusion

• Next Topic: Redux reactions in living organisms
• Emphasis on understanding ATP's role as an energy carrier due to its high-energy anhydride bonds.