Q.70 Match List I with List II
| LIST I | LIST II |
|---|---|
| A. Auxins B. Cytokinins C. Ethylene D. Gibberellins |
I. 2-chloroethyl phosphonic acid II. Tetracyclic diterpenoids III. Dichlorophenoxyacetic acid IV. Furfurylamino purine |
Choose the correct answer from the options given below:
(B) A-I, B-IV, C-II, D-III
(C) A-III, B-IV, C-I, D-II
(D) A-I, B-IV, C-III, D-II
The correct answer is option (C): A-III, B-IV, C-I, D-II. This matching question tests knowledge of plant hormones and their specific chemical representatives or structures.
Correct Matching
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A. Auxins → III. Dichlorophenoxyacetic acid: This refers to 2,4-D (2,4-Dichlorophenoxyacetic acid), a synthetic auxin used as a herbicide that mimics natural auxins like IAA to promote cell elongation and inhibit growth in broadleaf weeds.
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B. Cytokinins → IV. Furfurylamino purine: This is kinetin (6-furfurylaminopurine), a cytokinin that promotes cell division, shoot formation, and delays senescence in plants.
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C. Ethylene → I. 2-chloroethyl phosphonic acid: Known as ethephon (2-chloroethylphosphonic acid), it releases ethylene gas, regulating fruit ripening, senescence, and abscission.
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D. Gibberellins → II. Tetracyclic diterpenoids: Gibberellins (GAs) are tetracyclic diterpenoid acids that stimulate stem elongation, seed germination, and flowering.
Option Analysis
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(A) A-III, B-I, C-IV, D-II: Incorrect. B (Cytokinins) mismatches with I (ethephon, ethylene releaser); C (Ethylene) mismatches with IV (kinetin).
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(B) A-I, B-IV, C-II, D-III: Incorrect. A (Auxins) mismatches with I (ethephon); C (Ethylene) mismatches with II (GA structure); D mismatches with III (2,4-D).
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(C) A-III, B-IV, C-I, D-II: Correct, as detailed above.
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(D) A-I, B-IV, C-III, D-II: Incorrect. A mismatches with I (ethephon); C mismatches with III (2,4-D).
Introduction to Auxins Cytokinins Ethylene Gibberellins Matching
In plant physiology exams like NEET, questions on Auxins Cytokinins Ethylene Gibberellins matching List I List II test core knowledge of phytohormones and their chemical identities. This includes linking Auxins to Dichlorophenoxyacetic acid, Cytokinins to Furfurylamino purine, Ethylene to 2-chloroethyl phosphonic acid, and Gibberellins to Tetracyclic diterpenoids. Understanding these matches is key for scoring in plant growth regulators sections.
Key Chemical Identities
Auxins like Dichlorophenoxyacetic acid (2,4-D) promote apical dominance and are synthetic herbicides.
Cytokinins such as Furfurylamino purine (kinetin) drive cell division and bud formation.
Ethylene via 2-chloroethyl phosphonic acid (ethephon) induces ripening and senescence.
Gibberellins are Tetracyclic diterpenoids that elongate stems and break dormancy.
Why This Matching Matters for Exams
These plant hormones regulate growth, and mismatches like confusing ethephon with auxins lead to errors in options (A), (B), or (D). Option (C) perfectly aligns List I (Auxins, Cytokinins, Ethylene, Gibberellins) with List II.
