Photosynthesis Flashcards
Where does photosynthesis generally occur?
in mesophyll cells with abundant chloroplasts
Light reactions (3 facts)
light-dependent reactions
occur in the thylakoid membrane (which contains phtosystems 1 and 2)
convert light energy into chemical energy -NADPH
Where do light reactions occur?
thylakoid membranes , and the protons are pumped from the stroma into the thylakoid space
Photosynthesis simple reaction
6 CO₂ + 12 H₂O — (light)—> C₆H₁₂O₆ + 6O₂ + 6H₂O
What type of process is photosynthesis and what is its electron carrier?
redox (reduction-oxidation)
the electron carrier is NADP⁺
Photophosphorylation
Electrons are transported through a series of thylakoid membrane proteins (creating a proton gradient inside the thylakoid) when the protons go back to the stroma though ATP synthase, they help in the synthesis of ATP
Photosystem
- light harvesting complex
Includes
- chlorophyll a,b and other pigments
- reaction center (specialized chlorophyll a molecules to emit exited electrons)
- the primary electron acceptor
Photosystem 1
- Reduced NADP+ in non-cyclic photophosphorylation
- ATP synthesis
- Present in both cyclic and noncyclic phosphorylation
Photosystem 2
- splits water
- ATP synthesis
- functions only in non-cyclic phosphorylation
Cyclic photophosphorylation
- water is not split
-oxygen is not evolved - NADPH is not made
Where and when does cyclic phosphorylation occur?
- in primitive plants
- when NADH is derived from another pathway
- when there is abundant NADH
What are the three major stages of the Calvin cycle?
- carbon fixation
- reduction
- regeneration of RuBP
Key regulatory step of Calvin cycle
- step 1
- it is a carbon fixation reaction
-CO₂ is combined with RuBP to generate two 3-C compounds 3-phosphoglycerate by the enzyme rubisco
- controls the synthesis of sugars by CO₂ fixation
What is photorespiration in simple terms?
Fixing O₂ into RuBP
