Photosynthesis- Light dependent reaction Flashcards
During photosynthesis, the energy used to make ATP is supplied from what?
Light energy
What is phosphorylation?
The addition of a phosphate group to ADP
How is ATP hydrolysed
-ATP + H20 —–> ADP +Pi
-Hydrolisis reaction
-ATP hydrolase
How is ATP synthesised?
-ADP + Pi —-> ATP +H20
-Condensation reaction
-ATP synthase
What is photophosphyrlation?
-The energy to make ATP is supplied by light
Why is ATP used?
-To provide energy for the light-independent reaction
Oxygen:
Oxidation is gain
Reduction in loss
Hydrogen and electrons:
Oxidation is loss
Reduction is gain
What is the 1st step of the light-independent reaction?
-Light is absorbed by chlorophyll molecules
-Photoionization
What is photoionisation?
-When electrons excited to higher energy levels
What is the 2nd step of the light-independent reaction?
-These electrons are passed from one carrier to another in the electron transfer chain
-During each transfer, ATP is released
-This energy is used to pump protons across membranes into the thylakoid
-As the protons move back across the membrane in the stroma, ATP synthase Catalyses the production of ATP
What is the 3rd step of the light-independent reaction?
Electrons from the 1st chlorophyll molecule are transferred to a 2nd chlorophyll molecule
What is the 4th step of the light-independent reaction?
-Excited electrons from the 2nd chlorophyll molecules are accepted by NADP (which also receives hydrogen ions from water)
-The NADP is reduced
-Reduced NADP supplies hydrogen and energy for light-independent reactions
What is the 5th step of the light-independent reaction?
-Water is split (photolysis) releasing oxygen, hydrogen ions and electron
What is the 6th step of the light-independent reaction?
-Electrons from the water replace the electrons lost from the 1st chlorophyll molecule
When is ATP catalysed?
When protons move back across the membrane
