ATP

Question 1

What are the main biological energy requiring processes?

Answer 1

• synthesis (e.g. proteins)
• transport (e.g. active transport)
• movement (e.g. muscle contraction)

Question 2

What makes up an ATP molecule?

Answer 2

• 3 phosphate heads (can be added or removed)
• ribose sugar
• nitrogenous base adenine

Question 3

Why is ATP known as the universal energy currency?

Answer 3

It’s used for energy transfer in all cells of all living things.

Question 4

How does ATP release energy?

Answer 4

• small amount of energy needed to break weak bond holding last phosphate group in ATP
• a lot more energy is released: 30.6kJ
• hydrolysis reaction as water needed
• hydrolysed into adenine diphosphate (ADP) and a phosphate ion

Question 5

How is ATP created?

Answer 5

• reattaching a phosphate group to an ADP molecule
• condensation reaction as water removed
• called phosphorylation

Question 6

Why is it better that cells have ATP as an intermediate energy source rather than using glucose?

Answer 6

• ATP releases its energy instantly in a single reaction

- hydrolysis of ATP releases a small amount of energy, ideal for fuelling reactions in the body

Question 7

How is ATP ideally suited to carry out its function in energy transfer in cells?

Answer 7

• small so easy to move in and out of cells/organelles (mitochondria)
• water soluble (energy requiring processes happen in aqueous environment)
• bond between phosphates with intermediate energy (large enough to be useful for cellular reactions but not too large that energy is wasted as heat)
• releases energy in small quantities
• easily regenerated

Question 8

Why don’t cells store large amounts of energy as ATP? How are large amounts of energy stored instead?

Answer 8

• ATP relatively unstable
• energy stored as fats and carbohydrates
• during cellular respiration fats and carbohydrates are broken down releasing energy used to make ATP