1.6.2 Hydrolysis & Synthesis of ATP

Question 1

Energy released during the reactions of respiration is transferred to the molecule

Answer 1

adenosine triphosphate (ATP)

Question 2

ATP is a small and soluble molecule that provides

Answer 2

a short-term store of chemical energy that cells can use to do work

Question 3

The use of ATP as an ‘energy-currency’ is beneficial for many reasons, the hydrolysis of ATP can be carried out

Answer 3

quickly and easily wherever energy is required within the cell by the action of just one enzyme, ATPase

Question 4

The use of ATP as an ‘energy-currency’ is beneficial for many reasons, a useful

Answer 4

quantity of energy is released from the hydrolysis of one ATP molecule - this is beneficial as it reduces waste but also gives the cell control over what processes occur

Question 5

ATP is relatively stable at

Answer 5

cellular pH levels

Question 6

Hydrolysis of ATP to adenosine diphosphate (ADP) and an inorganic phosphate group (Pi) is catalysed by the enzyme

Answer 6

ATP hydrolase sometimes called ‘ATPase’

Question 7

The hydrolysis of ATP can be coupled to energy-requiring reactions within cells such as

Answer 7

• the active transport of ions up a concentration gradient
• enzyme controlled reactions that require energy
• muscle contraction and muscle fibre movement

Question 8

As ADP forms free energy is released that can be used for processes within a cell eg

Answer 8

DNA synthesis

Question 9

As ADP forms free energy is released that can be used for processes within a cell eg DNA synthesis:q

Answer 9

• removal of one phosphate group from ATP releases 30.8 kJ mol -1 of energy, forming ADP
• removal of a second phosphate group from ADP also releases 30.8 kJ mol-1 of energy, forming AMP
• removal of the third and final phosphate group from AMP releases 14.2 kJ mol-1 of energy, forming adenosine

Question 10

The inorganic phosphate released during the hydrolysis of ATP can be used to

Answer 10

phosphorylate other compounds, often making them more reactive

Question 11

Features of ATP Table

Answer 11

Question 12

ATP is formed when

Answer 12

ADP is combined with an inorganic phosphate (Pi) group by the enzyme ATP synthase

Question 13

ATP is formed when ADP is combined with an inorganic phosphate (Pi) group by the enzyme ATP synthase

Answer 13

• this is an energy-requiring reaction
• water is released as a waste product (therefore ATP synthesis is a condensation reaction)

Question 14

ATP is made during the reactions of

Answer 14

respiration and photosynthesis

Question 15

ATP can be made in two different way

Answer 15

• substrate-linked phosphorylation (occurs in the glycolysis stage of respiration)
• chemiosmosis (occurs in the electron transport chain stage of respiration)