1.6 ATP

Question 1

Structure of ATP.

Answer 1

• Three phosphate groups (triphosphate)
• A ribose sugar attached to adenine (adenosine)

Question 2

Hydrolysis of ATP is catalysed by …

Answer 2

ATP hydrolase.

Question 3

The hydrolysis of ATP forms which products?

Answer 3

ADP + Pi (Inorganic phosphate)

Question 4

What is ATP?

Answer 4

ATP is a short-term store of chemical energy and is used to transfer energy in all energy-requiring processes in cells.

Question 5

Why is ATP described as universal?

Answer 5

It is used in all organisms.

Question 6

Give 2 ways in which the hydrolysis of ATP is used in cells.

Answer 6

1. To provide energy for other reactions that require it
2. To add phosphate to other substances and make them more reactive

Question 7

How is ATP synthesised?

Answer 7

Condensation reaction between three phosphates, adenine and ribose, catalysed by ATP synthase.

Question 8

Describe how ATP is re-synthesised in cells.

Answer 8

Re-synthesised from ADP and Pi by ATP synthase during respiration/photosynthesis

Question 9

What features of ATP make it beneficial?

Answer 9

1. Releases a small but sufficient amount of energy → minimises energy wastage
2. Stable molecule → won’t be broken down unless a catalyst is present
3. Can be rapidly recycled / re-synthesised → same molecule can be reused elsewhere in the cell for different reactions
4. Hydrolysis is quick → releases energy instantaneously to respond to sudden increase in energy demand
5. Phosphorylates other compounds (i.e. metabolites) → making them more reactive
6. Is not lost from cells → new ATP does not need to synthesised
7. Soluble and moves easily within cells → can transport energy to different areas in the cell

Question 10

ATP vs DNA nucleotide.

Answer 10

Number of phosphates: ATP (3) / DNA (1)
Nitrogenous Base(s): ATP (Adenine) / DNA (ATCG)
Sugar: ATP (Ribose) / DNA (Deoxyribose)