NEET Previous Year Pattern Analysis — PP-03

High-Frequency Question Types

Category 1 — Direct PGR Function (2–3 questions/year) Most common question format: "Which hormone does [function]?"

• Gaseous hormone → Ethylene ($C_{2}H_{4}$)
• Stress hormone → ABA
• Causes bolting → Gibberellin
• Aleurone layer alpha-amylase → Gibberellin
• Delays senescence (Richmond-Lang) → Cytokinin
• Apical dominance → Auxin
• Stomatal closure → ABA
• Triple response → Ethylene
• Feminization in cucumber → Ethylene

Category 2 — Photoperiodism Classification (1–2 questions/year) Commonly tested: Rice = SDP; Wheat = LDP; Tomato = DNP; Chrysanthemum = SDP; Spinach = LDP. Also tested: "Which is a short-day plant?" with Xanthium as correct answer; Phytochrome mediates photoperiodism (Pr/Pfr forms).

Category 3 — Chemical Nature of PGRs (1 question/year) Commonly asked: "Cytokinins are derived from..." → Adenine. Traps: Both GA and ABA are terpenoids; students confuse them. Auxin = Indole compounds. Ethylene = gaseous hydrocarbon.

Category 4 — Differentiation Types (1 question every 2 years) Example: "Interfascicular cambium from parenchyma = ___" → Dedifferentiation. "Secondary xylem from cambium = ___" → Redifferentiation.

Category 5 — Named Discoveries (occasional) Went + Avena = Auxin; Kurosawa + Gibberella = Gibberellin; Skoog and Miller + herring sperm DNA = Cytokinin (Kinetin); Cousins + gas burners = Ethylene; Addicott & Carns = ABA.

Top 5 Most Tested Individual Facts

1. Ethylene = only gaseous hormone
2. ABA = stress hormone
3. $GA_{3}$ induces alpha-amylase in aleurone layer of barley
4. Richmond-Lang effect = cytokinin delays senescence
5. Rice = SDP; Wheat = LDP; Tomato = DNP