Emerson's enhancement effect and Red drop have been instrumental in the discovery of:
Answer: (B) Two photosystems operating simultaneously. Emerson's enhancement effect and the Red drop revealed that photosynthesis is driven by two distinct photochemical systems acting together.
- A.Photophosphorylation and non – cyclic electron transport
- B.Two photosystems operating simultaneously✓
- C.Photophosphorylation and cyclic electron transport
- D.Oxidative phosphorylation
Correct Answer
(B) Two photosystems operating simultaneously
Solution & Explanation
Emerson's enhancement effect and the Red drop revealed that photosynthesis is driven by two distinct photochemical systems acting together. NCERT states the pigments are organised into two discrete light-harvesting complexes within Photosystem I (P700) and Photosystem II (P680), which work in series; quantum yield is enhanced when both operate simultaneously rather than PS II alone beyond 680 nm. Hence the discovery is of two photosystems (B), not merely a single phosphorylation mode. NCERT: Class 11 Ch 11, p.138 [138:019–138:022]: "The pigments are organised into two"