Chapter 3 - ATP

Question 1

Cells require energy for which 3 main types of activity?

Answer 1

• synthesis - e.g. of large molecules such as proteins
• Transport - e.g. active transport
• Movement

Question 2

Why is ATP known as the universal energy currency?

Answer 2

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

Question 3

How ATP releases energy?

Answer 3

• A small amount of energy is needed to break the weak bond holding the last phosphate group in ATP
• A large amount of energy is released when the liberated phosphate undergoes other reactions involving bond formation

Question 4

Why is ATP -> a hydrolysis reaction?

Answer 4

water is involved in the removal of the phosphate group

Question 5

ATP -> reaction?

Answer 5

ATP + WATER -> ADP + phosphate group (Pi) + energy

Question 6

why is ATP not a good long term energy store?

Answer 6

the instability of phospjhate bonds in ATP

Question 7

How is ATP formed ?

Answer 7

The energy released in the breakdown of fats and carbs through respiration is used to create ATP. This occurs through reattaching a phosphate group to an ADP molecule - phosphorylation

Question 8

why is ATP a good immediate energy store?

Answer 8

• due to instability, cells do not store large amounts
• But it’s rapidly formed by phosphorylation of ADP
• this is happening constantly so large store of ATP not needed

Question 9

Properties of ATP?

Answer 9

• Small - easily moves in/ out of cells
• Water soluble - energy requiring processes happen in aqueous envirs
• releases energy in small quantities
• easily regenerated - can be recharged with energy
• contains bonds between phosphates with intermediate energy

Question 10

when ATP is hydrolysed, what is released?

Answer 10

a small packet of energy

Question 11

energy released can be used for?

Answer 11

• active transport
• protein synthesis
• muscle contraction
• chromosome movement during cell /

Question 12

what is an exergonic reaction?

Answer 12

Reactions that release energy

Question 13

what is an endergonic reaction?

Answer 13

Reactions that require an input of energy

Question 14

3 ways ATP can be synthesised?

Answer 14

1. Photophosphorylation - in chloroplasts
2. Oxidative Phosphorlyation
3. Substrate level phosphorylation

Question 15

What us photophosphorylation?

Answer 15

ATP is synthesised during photosynthesis using light energy - occurs in chloroplasts

Question 16

What is oxidative phosphorlyation ?

Answer 16

ATP can also be synthesised by using energy from energy from electron transfers during respiration - mitochondria in plant and animal cells

Question 17

what is substrate level phosphorylation?

Answer 17

ATP can also be synthesised by transferring Pi from donor molecules to ADP during respiration - cell cytoplasm and mitochondria in p + a cells