Importance of ATP Flashcards
What is ATP?
Adenosine triphosphate is the universal energy carrier found in all living cells.
Where is ATP produced?
Is synthesised in the internal membranes of mitochondria and chloroplasts.
Describe how ATP is synthesised.
- Involves ATP synthase, an enzyme found embedded in cellular membranes.
- ATP synthase phosphorylates ADP to form ATP as protons flow through it, down an electrochemical gradient.
Compare the flow of protons across the mitochondrial and chloroplast membranes.
Mitochondrial membrane - H ions flow across the inner membrane, from the inter membrane space into the matrix.
Chloroplast membrane - H ions flow across the thylakoid membrane, from the thylakoid space into the stroma.
Chemiosmosis
The synthesis of ATP through the movement of protons down their electrochemical gradient across a partially permeable membrane, catalysed by ATP synthase. As protons move down, energy is released for the attachment of an inorganic phosphate to ADP forming ATP.
How is the proton gradient maintained during chemiosmosis?
Potential energy associated with excited electrons is coupled to the active transport of H ions across the membrane by proton pumps.
Electron transport chain
A series of electron carrier proteins each with progressively lower energy levels that transfer electrons in a chain of oxidation-reduction reactions, forming a gradient of protons that enable ATP synthesis.
How can dehydrogenase activity in chloroplasts be investigated?
Using artificial hydrogen acceptors such as DCPIP, methylene blue and tetrazolium compounds.
What colour change is observed when DCPIP is reduced?
Blue to colourless.
