2.3 - ATP

Question 1

Uses of ATP in the body (5):

Answer 1

1. movement and contraction of muscles
2. molecules requiring active transport to move against the conc gradient
3. synthesis of large molecules
4. secretion of substances from cells - releasing hormones from glands
5. Phosphorylation of molecules - makes them more reactive

Question 2

Structure of ATP (3):

Answer 2

• a nucleotide derivative
• contains adenine, ribose and 3 phosphate groups

Question 3

What is ATP?

Answer 3

a molecule involved in energy transfer

Question 4

ATP reactions (2):

Answer 4

• Hydrolysis - addition of water to break ATP into ADP and Pi - catalysed by ATP hydrolase - releases energy
• condensation - removal of water to form ATP from ADP and Pi - catalysed by ATP synthase - requires energy and traps chemical energy in the bond

Question 5

Properties of ATP and its relation to its function (6):

Answer 5

1. Hydrolysis of ATP releases a small amount of energy - little is lost as heat
2. ATP is broken in one step - its quick
3. ATP is rapidly resynthesised - readily available
4. Pi can phosphorylate other compounds - more reactive
5. bonds between phosphates are unstable - easily broken (low Ea)
6. ATP is soluble - easily transported