- A De novo synthesis of additional chlorophyll molecules occurring within minutes of bright illumination
- B Reversible phosphorylation of LHCII, which migrates between PS II and PS I to balance excitation
- C Light-driven activation of Rubisco carboxylase by specialized Rubisco activase enzymes nearby
- D Rapid stomatal pore opening triggered directly by specific blue light photoreceptors present
Correct answer: B. Reversible phosphorylation of LHCII, which migrates between PS II and PS I to balance excitation
Explanation: State transitions: excess excitation of PS II activates STN7 kinase, which phosphorylates LHCII. Phospho-LHCII migrates to PS I (state 2). PPH1/TAP38 phosphatase reverses this, returning to state 1.
Concept context
Light reactions, the Calvin cycle, C3/C4/CAM pathways, photorespiration, and factors affecting the rate of photosynthesis. One of the highest-yield NEET chapters.