3.1.6

Question 1

Draw ATP

Answer 1

adenine - ribose - Pi - Pi - Pi

Question 2

What is ATP made of?

Answer 2

Adenine (a base)
Ribose (a pentose sugar)
3 phosphate groups

Question 3

Explain the significance of ATP

Answer 3

Metabolic processes- provides energy to build macromolecules from their basic units
Movement- provided energy needed for muscle contraction as energy is needed for the filaments to slide over eachother
Active transport- provided energy needed to change shape of carrier proteins in plasma membrane to move molecules against conc gradient
Secretion- used to form lysosomes
Activation of molecules- inorganic phosphate can phosphorylate other compounds increasing reactivity

Question 4

Describe the hydrolysis of ATP

Answer 4

Hydrolysis reaction- requires water
ATP converted to ADP and inorganic phosphate
Enzyme ATP hydrolase catalyses reaction
Hydrolysis of ATP releases energy
Inorganic phosphate can be added to another compound- phosphorylation- which increases reactivity of compounds
ATP + water -> ADP + Pi + energy

Question 5

Describe the synthesis of ATP

Answer 5

Condensation reaction- released water
ADP and inorganic phosphate converted to ATP
Enzyme ATP synthase catalyses reaction
ATP is synthesised in photosynthesis and respiration
ADP + Pi -> ATP + water

Question 6

Describe the 3 ways ATP can be reformed

Answer 6

1. photophosphorylation- occurs in chlorophyll during photosynthesis
2. substrate level phosphorylation- when phosphate groups are transferred from donor molecules to ADP in photosynthesis
3. oxidative phosphorylation- occurs in mitochondria during electron transport chain (part of respiration)

Question 7

Why is ATP better than glucose?

Answer 7

Splitting of ATP into ADP and Pi releases energy in small manageable bursts
Hydrolysis of ATP into ADP and Pi is a single reaction whereas glucose breakdown requires a long series of reactions

Question 8

Why can we describe ATP as an immediate energy source?

Answer 8

Only one reaction needed to release energy from ATP

Question 9

Describe the advantages of ATP

Answer 9

Instant energy source
Single reaction to release energy
Releases small amounts of energy
Soluble- transports chemical energy to where it is needed in the cell
Universal energy carrier- can be used in many different chemical reactions