1.6 ATP

• Describe the structure of ATP

  • ● Ribose bound to a molecule of adenine (base) and 3 phosphate groups
  • ● Nucleotide derivative (modified nucleotide)

  
• Describe how ATP is broken down

  • ● ATP (+ water) → ADP (adenosine diphosphate) + Pi (inorganic phosphate)
  • ● Hydrolysis reaction, using a water molecule
  • ● Catalysed by ATP hydrolase (enzyme)
• Give two ways in which the hydrolysis of ATP is used in cells

  • ● Coupled to energy requiring reactions within cells (releases / provides energy)
  • ○ Eg. active transport, protein synthesis
  • ● Inorganic phosphate released can be used to phosphorylate (add phosphate to) other compounds, making them more reactive
• Describe how ATP is resynthesised in cells

  • ● ADP + Pi → ATP (+ water)
  • ● Condensation reaction, removing a water molecule
  • ● Catalysed by ATP synthase (enzyme)
  • ● During respiration and photosynthesis

  
• Suggest how the properties of ATP make it a suitable immediate source of energy for cells


  ● Releases energy in (relatively) small amounts / little energy lost as heat

  ● Single reaction / one bond hydrolysed to release energy (so immediate release)

  ● Cannot pass out of cell