• Principle molecule for storing and transferring energy for cell work and activation energy; converted by enzymes


  • Basically RNA adenine nucleotide with two more phosphates                                                     
  • Nitrogenous base (adenine) attached
  • Ribose sugar (carbohydrate)
  • Three phosphate groups
    • All negatively charged groups → VERY unstable/reactive → has lots of potential energy

ATP Hydrolysis

  • Releases free energy (-) by hydrolyzing the last (terminal) phosphate group
  • Inorganic phosphate used to add molecule that has phosphate
  • Powers cellular work:
    • Chemical Work – making chemical bonds                                                                                 
    • Transport Work – transporting materials in/out cells
    • Mechanical Work – physical movement (e.g. muscle contractions)

ATP Function

  • Energy coupling – use exergonic reaction of ATP hydrolysis to power endergonic reactions in the cell

Energy released is linked by shared/phosphorylated intermediate to endergonic reaction

ATP Regeneration

  • ATP cannot be made by the body, ATP is converted or recycled in the body
  • ATP Dehydration Synthesis: Net ATP made by phosphorylation when ADP combines with phosphate group using energy from molecule (ex: glucose)
    • ADP+Pi+free energy→ATP+H2O
      • Cycle recycles ADP and inorganic phosphate
  • ATP production increases in low pH cuz provides more H+ (energy)