3.11 - ATP

Question 1

Name 4 biological processes that require energy

Answer 1

• muscle contraction
• cell division
• transmission of nerve impulses
• memory formation

Question 2

Name three main types of activities cells need energy for AND name an example for each

Answer 2

• synthesis - protein synthesis
• transport - pumping ions/ molecules across cell membranes
  - moving vesicles through cytoskeleton
• movement - e.g. protein fibres in muscle cells for muscle contraction

Question 3

State the structure of ATP

Answer 3

• 3 phosphate groups
• a pentose sugar
• adenine (nitrogenous base)

Question 4

Why is it called universal energy currency?

Answer 4

It is used for energy transfer in all cells of all living things

Question 5

What type of reaction occurs when ATP breaks down

Answer 5

Hydrolysis reaction

Question 6

What does ATP break down into?

Answer 6

Adenosine diphosphate(ADP) and an inorganic phosphate ion (Pi)

Question 7

State the word equation for break down of ATP

Answer 7

ATP + water —> ADP + inorganic phosphate ion (Pi) + energy

Question 8

How much energy is approximately released when the free phosphate iron undergoes other reactions involving bond formations?

Answer 8

Approx 30.6kJmol-1

Question 9

Which need more energy? Energy required to break bond between last and second last phosphate groups or the energy released when free phosphate ion undergoes bond forming reactions.

Answer 9

Small amount of energy needed to break bond between last and second last phosphate groups. A lot more energy is released when free phosphate ion undergoes bond forming reactions

Question 10

What does ‘reactions are ‘coupled’’ mean?

Answer 10

Hydrolysis of ATP occurs in association with energy-requiring reactions - both reactions occur simultaneously

Question 11

Why is ATP not a good long-term energy store?

Answer 11

The bonds between the phosphate groups are unstable

Question 12

What energy source or material is broken down to create ATP?

Answer 12

Fats and carbohydrates are broken down through cellular respiration to release energy that is used to make ATP

Question 13

What is the type of reaction for when ATP is reformed?

Answer 13

Condensation

Question 14

What is the name of the reaction in which ATP is reformed?

Answer 14

Phosphorylation of ADP

Question 15

Describe the phosphorylation of ADP

Answer 15

Phosphate ion re-attaches itself to ADP

Question 16

Why don’t cells have a large store of ATP?

Answer 16

The rapid interconversion of ATP and ADP happens constantly in all living cells so cells do not need a large store of it - hence ATP is a good immediate energy store

Question 17

Name 5 properties of ATP

Answer 17

• small - moves easily into, out of and within cells
• water soluble - energy-requiring processes can occur in aqueous environments
• releases energy in small quantities - suitable to most cellular needs - energy not wasted as heat
• easily regenerated - can be recharged with energy
• contains bonds between phosphates with intermediate energy - energy is large enough for cellular reaction but not enough to be wasted as heat