NEET Photosynthesis — Most Tested Topics (2010–2025)
| Topic | Frequency | Question Types | Key NEET Answer |
|---|---|---|---|
| PS I vs PS II (P700 vs P680) | Very High (almost every year) | "Which PS splits water?", "Reaction centre of PS I is?" | PS II = P680 = water splitting; PS I = P700 = NADPH |
| Cyclic vs Non-cyclic products | Very High | "Products of cyclic photo.?" | Cyclic = ATP only |
| C3 vs C4 first stable product | High | "First stable product of C4?" | OAA/Oxaloacetate (4C) |
| Calvin cycle stoichiometry | High | "ATP required for 1 glucose?" | 18 ATP + 12 NADPH |
| Location of Calvin cycle | Medium-High | "Dark reaction occurs in?" | Stroma |
| Photorespiration | Medium | "Photorespiration absent in?" | C4 plants |
| Blackman's law | Medium | Graph interpretation | Factor in minimum = limiting |
| Kranz anatomy | Medium | "Kranz anatomy found in?" | C4 plants only |
| Van Niel's experiment | Medium | " source in photosynthesis?" | Water () |
| Z-scheme order | Medium | "PQ acts between which?" | Between PS II and Cyt b6f |
High-Value Prediction for NEET 2026
- Assertion-Reason on cyclic photophosphorylation OR PS II/PS I confusion
- Multi-step graph: Blackman's law with 2–3 factors
- C3 vs C4 comparison (first product, enzyme, anatomy)
- Calvin cycle stoichiometry (18 ATP trap)
- Application: Why photorespiration increases at high temperature