3.1.6 - ATP

Question 1

What is ATP?

Answer 1

Adenosine triphosphate

Question 2

Describe the structure of ATP

Answer 2

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

Question 3

Describe how ATP is broken down

Answer 3

● ATP (+ water) → ADP (adenosine diphosphate) + Pi (inorganic phosphate)

● This is a Hydrolysis reaction, using a water molecule

● This reaction is Catalysed by ATP hydrolase (enzyme)

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)
○ eg. 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 (enzyme)

● 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 / so little energy lost as heat

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

● Cannot pass out of cell