2.3 Energy and ATP

Question 1

What is ATP

Answer 1

Adenosine Triphosphate is a nucelotide derivative and is an immediate source of energy

Question 2

Describe the sturcture of ATP

Answer 2

A ribose bound to a molecule of Adenine-nitrogenous base- and 3 Phosphate groups
Nucleotide derivative

Question 3

Describe how ATP is broken down

Answer 3

ATP + water —> ADP(Adenosine diphosphate) + Pi (inorganic Phosphate)
Hydrolysis reaction using a water molecule
Catalysed by ATP hydrolase

Question 4

Give two ways in which the hydrolysis of ATP is used in cells

Answer 4

• Coupled to energy requiring reactions within cells which releases energy for Active transport or protein synthesis
• Inorganic phosphate released can be used to phosphorylate ( add phosphat to) other compounds making them more reactive

Question 5

Descrine 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 small amounts
Single reactions hydrolysed to release energy ( so immediate release)
Cannot pass out of cell

Question 7

How is ATP an immediate source of energy

Answer 7

When you break one of the bonds between the phosphate groups a small amount of energy is released to the surroundings

Question 8

What is phosphorylation

Answer 8

When an inorganic phosphate is released during the hydrolysis of ATP
It can be bonded on to different compounds to make them more reactive

Question 9

Give an example of phosphorylation

Answer 9

In the first stage of respiration glucose gets phosphorylysed to make it more reactive

Question 10

What are the 5 properties of ATP

Answer 10

• ATP releases a small amount of energy—> no energy is wasted
• ATP is a small and soluble molecule—> can be easily transported around the cell
• Only one bond needs to be hydrolysed in order to release energy which is why energy release is immediate
• Can transfer energy to another molecule by transferring one of its phosphate groups through phosphorylation making other compounds more reactive
• ATP cannot pass out of the cell—> cannot diffuse through the cell surface membrane and there are no protein carries that it can attach to so every cell has its own supply of ATP

Question 11

What is a benefit of no energy being wasted through the use of ATP

Answer 11

Cells do not over heat from wasted heat energy and cells are less likely to run out of resources