Photosyntheiss Flashcards
Where do the light independent reaction occur in plants?
Stroma of chloroplasts
Where do the light dependant reaction occur in plants?
In the thylakoids of chloroplasts
Explain the role of light in photoionisation
Chlorophyll molecules absorb energy from photons of light which excites electrons causing them to be released from the chlorophyll
Name the two main stages involved in ATP production in the light dependent reaction:
- electron transfer chain
- chemiosmosis
What happens in the electron transfer chain?
Electrons released from the chlorophyll move down a series of carrier proteins embedded in the thylakoid membrane and undergo a series of redox reactions which releases energy.
Explain the role of light in photolysis:
Light energy splits molecules of water into its H+ ions and electrons
What happens to the products of photolysis of water?
- H+ ions move out of the thylakoid space via ATP synthase and are used to reduce coenzyme NADP
- e- electrons replace electrons lost from chlorophyll
- 02-used for respiration or diffuse out of leaf as waste gas
How and where is reduced NADP produced in the light dependent reaction?
It is produced in the stroma and is catalysed by dehydrogenase enzymes.
NADP+2H+ +2e- ——> reduced NADP
Where do the H+ ions and electrons used to reduce NADP come from?
H+ ions come from the photolysis of water
Electrons- NADP acts as the final electron acceptor in the electron transfer chain
Name 3 main stages in the Calvin cycle:
- Carbon fixation
- reduction
- regeneration
What happens in carbon fixation?
Carbon dioxide reacts with ribulose bisphosphate(RuBP) which is catalysed by the enzyme rubisco to form unstable 6C intermediate which breaks down into 2 GP molecules
What happens during reduction?
The two GP molecules produced is reduced into two molecules of TP this required 2 reduced NADPs and 2 ATPs to form 2 NADP and 2 ADP
What is the stroma?
A fluid filled matrix where the light independent reaction takes place
The leaf of a plant that is adapted to living in shade will differ from the leaf of a plant that is adapted to living in sunlight.
Suggest one way in which the structure of these leaves will differ [f214 june 15 q1cii]
shade leaf will have
1 large(r) / more, chloroplast(s)/ (palisade) mesophyll; [more, chlorophyll/ photosystems]
2 more, grana/ thylakoids (in chloroplast);
3 large(r) surface area (of leaves);
Identify the enzyme that catalyses the fixation of carbon dioxide. [F214 June 14 q1bi]
rubisco / RuBP carboxylase / ribulose bisphosphate carboxylase; [ribulose biphosphate carboxylase]
