ATP Exam Questions/Key Markpoints

Question 1

Write a simple equation to shoe how ATP is synthesised from ADP

Answer 1

ADP + Pi –> ATP

Question 2

Give 2 ways in which the properties of ATP make it a suitable source of energy in biological processes

Answer 2

• Breaking of ATP occurs in 1 chemical reaction ADP +Pi–> ATP
• Energy is released in small manageable amounts
• ATP is soluble

Question 3

Humans synthesise more than their body mass of ATP each day. Explain why it is necessary for them to synthesise such a large amount of ATP

Answer 3

ATP only releases a small amount of energy at a time and it cannot be stored

Question 4

ATP is used in many biological processes. Explain why

Answer 4

• Energy released in small manageable amounts
• Only 1 chemical reaction to break down
• Can be reformed easily
• ATP can be used to phosphorylate molecules to become more reactive

Question 5

Describe how ATP is made in mitochondria

Answer 5

Acetyl CoA reacts with 4C compound and CoA is removed. This then makes a 6C compound is then decarboxylated and oxidised as well as NAD+ –> NADH by reduction. FAD2+ is also reduced to FADH and ADP+Pi–> ATP. This then further oxidises the 6C compound and gets decarboxylated to form a 5C compound. NADH is oxidised and loses H+ and e-. H+ gains energy from the excited electrons and moves up into the space between membrane. e- are in the electron transport chain. High concentration of H+ in the membrane space which means they use facilitated diffusion via ATP synthase. This then causes ADP+Pi —> ATP and hydrogen and oxygen combine to form water.

Question 6

Plants produce ATP in their chloroplasts during photosynthesis. They also produce ATP during respiration. Explain why it is important for plants to produce ATP during respiration in addition to during photosynthesis.

Answer 6

• ATP cannot be stored
• Plants use more ATP than they can make from photosynthesis alone
• There would be no ATP production in the dark if it was only photosynthesis
• All cells need ATP but some cells are unable to photosynthesise
• ATP is necessary for active transport also

Question 7

Explain why oxygen is needed for the production of ATP on the cristae of the mitochondrion

Answer 7

Oxygen is necessary as facilitated diffusion causes H+ to move down and electron transport chain brings e- which form hydrogen which combines with oxygen to form water. ADP + Pi —> ATP and the NADH is needed to restart the reaction as without oxygen this would not be possible.

• Oxygen is the terminal acceptor and electrons cannot be passed along the chain if no oxygen is there to accept