1.6 ATP

• What is ATP? Structure? Broken down?

  stands for Adenosine triphosphate

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

  ● Nucleotide derivative (modified nucleotide)

  ● 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
• Exam insight: common mistakes ❌- (1/5)

  ❌“ATP is adenine diphosphate.”

  ✅ATP is adenosine triphosphate.
• Exam insight: common mistakes ❌- (2/5)

  ❌“ATP has 3 phosphorus groups.”

  ✅ATP has 3 phosphate groups (PO4 3- ).
• Exam insight: common mistakes ❌- (3/5)

  ❌“ATP hydrolysis creates energy.”

  ✅Energy cannot be created - only transferred / released.
• Exam insight: common mistakes ❌- (4/5)

  ❌“ATP can be stored

  ✅ATP is too unstable to be stored within cells.
• Exam insight: common mistakes ❌- (5/5)

  ❌“The only use of ATP is energy release.”

  ✅The inorganic phosphate can be used to phosphorylate other compounds, making them more reactive.