1.6 ATP

Question 1

What is ATP

Answer 1

Adenine triphosphate

Question 2

Describe the structure of ATP

Answer 2

• ribose bound to a molecule of adenine and 3 phosphate groups
• nucleotide derivative

Question 3

Describe how ATP is broken down

Answer 3

• ATP (+water) = ADP (adenine diphosphate) + Pi (inorganic phosphate)
• hydrolysis reaction, using a water molecule
• catalysed by ATP hydrolase

Question 4

Give two ways in which the hydrolysis of ATP is used in cells

Answer 4

• coupled to energy requiring reactions within cells (releases energy)
  
  • e.g. active transport, protein synthesis
• inorganic phosphate released can be used to phosphorylate (add phosphate to) other compounds, making them more reactive

Question 5

Describe how ATP is resynthesised in cells

Answer 5

• ADP + Pi - ATP (+water)
• condensation reaction, removing a water molecule
• catalysed by ATP synthase
• during respiration and photosynthesis

Question 6

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

Answer 6

• 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