Plant Growth Regulator Classes — NEET Biology
✅ Asked in NEET 2026The plant growth regulators (PGRs) are small, simple molecules of diverse chemical composition. They could be indole compounds (indole-3-acetic acid, IAA); adenine derivatives (N6-furfurylamino purine, kinetin), derivatives of carotenoids (abscisic acid, ABA); terpenes (gibberellic acid, GA3) or gases (ethylene, C2H4). Plant growth regulators are variously described as plant growth substances, plant hormones or phytohormones in literature.
NTA focuses on the chemical classification of plant growth regulators, particularly that cytokinins are adenine derivatives with kinetin as the classic example. Students often confuse different PGR types and their chemical origins—they may mix up gibberellins (terpenes) with cytokinins or forget that ABA is a carotenoid derivative. The key is remembering: cytokinins = adenine derivatives (kinetin), gibberellins = terpenes, ABA = carotenoids, IAA = indole compounds, ethylene = gas. NEET repeatedly tests this classification because distinguishing PGR types by chemical structure is essential for understanding their distinct roles in plant development and growth regulation.
This paragraph was tested 2 times in NEET.
Match List-I (Growth Regulator) with List-II (Function/Effect) — A. 2,4-D, B. GA3, C. Kinetin, D. ABA.
Which of the following growth regulators is an adenine derivative? (NEET 2022 Phase 2)
Through deep analysis of NEET and NTA, 88 of 90 questions from the NEET 2026 paper were matched straight from the MedicNEET Biology question bank.
88/90MedicNEET's Biology question bank is built from the same NCERT lines NTA picks repeatedly. Not random MCQs — questions crafted exactly like NTA crafts them.