Photosynthesis Flashcards
Outline the light-dependant reaction
- Chlorophyll absorbs light / photoionization
- Energy released during photoionization is conserved in ATP + NADP production
- Electrons transfer down ETC
- Passage of protons travel across chloroplast membrane being catalysed by ATP synthase
- Water photolysis occurs (producing H+, O and electrons)
Outline the light-independent reaction
- CO2 reacts with ribulose bisphosphate (RuBP) to form 2x glycerate phosphate (GP)
- Catalysed by rubisco
- ATP + reduced NADP reduce GP to triose phosphate (TP)
(4. ATP comes from light dependant reaction) - Some TP regenerates RuBP
- Some TP is converted to organic substances
Where do the light-dependant and light-independent reaction take place?
Dependant = thylakoids
Independent = stroma
Explain the role of light during photoionization
Chlorophyll absorbs light energy
This excites 2 electrons that are then released from the chlorophyll
What happens in the electron transport chain (ETC)?
Electrons released from chlorophyll travel down carrier proteins embedded in membrane
Undergo a series of redox reactions
How does chemiosmosis produce ATP in the light-dependant reaction?
Protons move down their concn gradient
From thylakoid space into stroma
Via ATP synthase channel protein
What are the 3 main stages in the Calvin cycle?
- Carbon fixation
- Reduction
- Regeneration
How are chloroplasts structured to absorb light?
ATP synthase channels
Large S.A. for ETC
Chlorophyll is positioned for maximum light absorption
Explain the roles of ATP and reduced NADP in the light-independent reaction
ATP = reduction of GP to TP
NADP = transports electrons for reduction of GP to TP
Name 4 limiting factors of photosynthesis
Light intensity
CO2 levels
Temperature
Mineral levels
What is a limiting factor?
Determines maximum rate of reaction
(even if other factors change)
