Pg132

• ATP molecule


  • One adenine (a nitrogenous base), one ribose sugar and three phosphate groups
  • Covalent bonds between phosphates groups are high-energy bonds
• ATP


  • The currency of energy of a cell
  • A cell with more ATP is able to do more work
• Breakdown of ATP


  1. Cell needs energy

  2. One bond between phosphate groups is broken

  3. Releases 7.3 kcal (7,300 calories) energy

  4. One inorganic phosphate (Pi) separates

  5. ATP is converted to ADP (Adenosine Diphosphate)
• Formation of ATP


  1. Cell has energy

  2. One inorganic phosphate (Pi) combines with ADP

  3. ATP is formed
• ATP molecules are constantly broken by the cell into ADP and inorganic phosphate and energy is obtained
• ATP molecules are constantly regenerated from ADP and phosphate using energy released from the breakdown of food
• This is how constant cycle of ATP breakdown and reformation goes on in the living cells