Zusammenfassung der Ressource
2.3 Energy and ATP
- Plant cells and animal cells release energy from glucose - respiration
- However, cells cant get their energy directly from glucose
- In respiration, the energy released from glucose is used to make ATP (adenosine triphosphate)
- Structure of ATP
- Adenine - a nitrogen-containing organic base
- Ribose - a pentose sugar that acts as a backbone to which other parts are attached
- Phosphates - a chain of three phosphates
- It is the bonds between these
phosphates where the
energy is stored. It is
released via hydrolysis
reactions
- How ATP stores energy
- Bonds between
phosphate groups are
unstable = they have
low activation energy = easily broken
- When broken these bonds release lots of energy
- Hydrolysis of ATP
- ATP + (H2O) --> ADP + Pi + E
- adenosine triphosphate + water --> adenosine diphosphate + inorganic phosphate + ENERGY
- Water used to convert ATP to ADP = hydrolysis reaction
- Reaction catalysed by the enzyme ATP Hydrolase
- The hydrolysis of ATP can be coupled to energy-requiring cells
- Energy used directly instead of being lost as heat
- Synthesis of ATP
- Catalysed by ATP synthase
- Reverse of the equation for the hydrolysis of ATP
- Water removed in process = Condensation reaction
- Adding an inorganic phosphate to adenosine diphosphate = adenosine triphosphate
- PHOSPHORYLATION
- synthesis of ATP from ADP occurs in 3 ways:
- In chlorophyll-containing plant cells
during photosynthesis
(photophosphorylation)
- In plant and animal cells
during respiration
(oxidative
phosphorylation)
- In plant and animal
cells when phosphate
groups are transferred
from donor molecules
to ADP (substrate-level
phosphorylation)