ATP

Question 1

What enzyme catalyses the breakdown on ATP?

Answer 1

ATP hydrolase enzyme

Question 2

How can inorganic phosphate (released by breakdown of ATP) be used?

Answer 2

It can be used to phosphorylate another compound/ added to another compound, which often makes the compound more reactive.

Question 3

The movement of calcium ions across a cell membrane can occur via the energy-requiring process of active transport.
This movement of calcium ions is coupled to the breakdown of ATP.
Suggest why.

Answer 3

The breakdown/hydrolysis of AT releases energy, so when this reaction/hydrolysis is coupled to the process of active transport it provides the energy for this process directly.

Question 4

ATP is an energy source used in many cell processes. Give two ways in which ATP is a suitable energy source for cells to use.
2 marks

Answer 4

Releases relatively small amount of energy / little energy lost as
heat;
(Key concept is that little danger of thermal death of cells)

Releases energy instantaneously;
Key concept is that energy is readily available

Phosphorylates other compounds, making them more reactive;

Can be rapidly re-synthesised;

Is not lost from / does not leave cells.

Question 5

Cells constantly hydrolyse ATP to provide energy.
(a) Describe how ATP is resynthesised in cells.

2 marks

Answer 5

From ADP and phosphate;

2. By ATP synthase;
3. During respiration/photosynthesis

Question 6

Scientists investigated treatment of a human bladder infection caused by a species of bacterium. This species of bacterium is often resistant to the antibiotics currently used for treatment.
They investigated the use of a new antibiotic to treat the bladder infection. The new antibiotic inhibits the bacterial ATP synthase enzyme.

The new antibiotic is safe to use in humans because it does not inhibit the
ATP synthase found in human cells.
Suggest why human AT synthase is not inhibited and bacterial synthase is inhibited.
1 mark

Answer 6

Human ATP synthase has different teriary structure to bacteria ATP synthase

Human ATP synthase has a different shape active site to bacterial ATP synthase

Antibiotic cannot enter human cells/mitochondria

Antibiotic not complementary (to human ATP synthase);

Question 7

What are ATP component molecules

Answer 7

Adenine
Ribose
3 phosphates

Question 8

Give two ways in which hydrolysis of ATP is used in cells
2 marks

Answer 8

1. To provide energy for other reactions/named process;
   Reject ‘produce’ energy
2. To add phosphate to other substances and make them more reactive/change their shape;

Question 9

Suggest and explain a procedure the scientists could use to stop the reaction. When investigating effect of concentration of Pi on ATP synthesis activity?
2 marks

Answer 9

Mark in pairs - eg. 1 and 2 = 2marks

1. Boil or add strong acid/alkali
2. Denatures ATP synthase
3. Put in ice/fridge/freezer
4. Lower kinetic energy so no enzyme substrate complex formed
5. Add high conc of inhibitor
6. Esc do not form

Question 10

What happens if you increase concentration of Pi

Answer 10

More enzyme substrate complex’s are formed = increase ATP concentration