1.6 ATP

• What is ATP?

  Adenosine triphosphate
• 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