1.6 ATP

• what is ATP

  adenosine triphosphate
• structure of ATP

  ribose bound to a molecule of adenine (base) and 3 phosphate groups

  nucleotide derivative (modified nucleotide)
• how ATP is broken down

  ATP (+ water) -> ADP (adenosine diphosphate) + Pi (inorganic phosphate)

  hydrolysis reaction using a water molecule

  catalysed by ATP hydrolyse (enzyme)
• two ways the hydrolysis of ATP is used in cells

  coupled to energy requiring reactions within cells (releases/provides energy)

  e.g active transport or protein synthesis

  inorganic phosphate released can be used to phosphorylate (add phosphate to) other compounds making them more reactive
• how is ATP resynthesises in cells

  ADP + Pi -> ATP (+ water)

  condensation reaction removing a water molecule

  catalysed by ATP synthase (enzyme)

  during respiration and photosynthesis
• how the properties of ATP make it a suitable immediate source of energy for cells


  releases energy is (relatively) small amounts/little energy lost as heat

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

  cannot pass out of cell