[2.3] ATP

Question 1

what is ATP made of?

Answer 1

• 1 adenine (nitrogen containing base)
• ribose (5 carbon sugar)
• 3 phosphate groups in a chain

Question 2

what does ATP stand for?

Answer 2

adenosine 5’ triphosphate

Question 3

what does ADP and AMP stand for?

Answer 3

• adenosine 5’ diphosphate
• adenosine 5’ monophosphate

(guess the difference lmaoo)

Question 4

how is ATP a large source of energy?

Answer 4

• ℗ - ℗ - ℗
• 1st chain = little energy
• 2nd chain = some energy
• 3rd chain = a lot of energy
• phosphate chain is easily broken down to release energy

Question 5

why is the last phosphate usually the first one to be removed?

Answer 5

bonds between 2nd and 3rd phosphate groups are unstable so have low activation energy

Question 6

where is ATP formed?

Answer 6

in the mitochondria

Question 7

how is ATP broken down?

Answer 7

• the enzyme ATP hydrolase (ATPase) breaks down ATP into ADP and Pi (inorganic phosphate) in a hydrolysis reaction
• ATP + H₂O -> ADP + Pi + energy

Question 8

how is ATP formed?

Answer 8

enzyme ATP synthase makes ATP from ADP and Pi in a condensation reaction

Question 9

what are some uses of energy from ATP? [6]

Answer 9

• movement
• secretion of molecules
• metabolic processes
• active transport
• polymerisation reactions eg. starch
• molecule activation

Question 10

how is energy from ATP used for movement?

Answer 10

ATP provides energy for muscle contraction

Question 11

how is energy from ATP used for metabolic processes?

Answer 11

ATP provides energy to build big molecules

Question 12

how is energy from ATP used in active transport?

Answer 12

to move particles against a concentration gradient

Question 13

how is energy from ATP used for molecule activation?

Answer 13

phosphorylate compounds lower activation energy for enzyme controlled reactions

Question 14

why is ATP so useful in biological processes? [5]

Answer 14

• releases energy in smaller, more manageable amounts
• energy is released quickly as there is one step with only one enzyme, ATPase
• released inorganic phosphate can also be used
  > can be added to another compound which makes it more reactive and thus lowers its activation energy
• releases energy instantaneously
• cannot leave cells so cannot be lost

Question 15

what are the 3 ways in which ATP synthesis can occur?

Answer 15

1. during respiration - oxidative phosphorylation
2. during photosynthesis - photophosphorylation
3. directly through phosphate group transfer in cells - substrate level phosphorylation, which occurs in the cytoplasm

Question 16

why does a lot of ATP need to be synthesised?

Answer 16

ATP:

• cannot be stored
• is an immediate store of energy
• only releases a small amount of energy in cells
• contains just enough energy to power one other metabolic reaction in the cell

Question 17

what does it mean that ATP is a universal energy carrier?

Answer 17

it is the form of chemical energy which is found in all living cells

Question 18

what are some uses of energy released in hydrolysis of ATP?

Answer 18

• used to phosphorylate another molecule
• hydrolysis reaction provides energy for endergonic reactions (ie. they take in energy)

eg. polymerisation reaction

Question 19

how is energy stored during a condensation reaction?

Answer 19

• energy in so catabolic
• exergonic reaction, which means energy released is stored in the bond between the 2nd and 3rd phosphate molecule