Abscisic Acid & Ethylene — NEET Biology MCQs with Solutions
Free NEET Biology Abscisic Acid & Ethylene MCQs with step-by-step solutions (6 questions). Part of Plant Growth and Development. Practise online on Prepizo — no login needed.
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Questions with solutions
Q1 — Abscisic Acid & Ethylene · easy · theory
The hormone known as the "stress hormone", which promotes stomatal closure during water stress, is:
A. Abscisic acid (ABA) ✓ Correct
B. Auxin
C. Gibberellin
D. Cytokinin
Solution: ABA closes stomata under drought stress and is a general growth inhibitor.
Q2 — Abscisic Acid & Ethylene · easy · theory
The gaseous plant hormone that promotes fruit ripening is:
A. Auxin
B. Ethylene ✓ Correct
C. Abscisic acid
D. Gibberellin
Solution: Ethylene is the only gaseous hormone; it hastens ripening and senescence.
Q3 — Abscisic Acid & Ethylene · medium · theory
Abscisic acid is antagonistic to gibberellins because ABA:
A. Causes cell division
B. Promotes bolting
C. Breaks seed dormancy
D. Induces and maintains seed dormancy (GA breaks it) ✓ Correct
Solution: ABA promotes dormancy and inhibits germination; gibberellin does the opposite — they are antagonists.
Q4 — Abscisic Acid & Ethylene · medium · theory
Ethylene is used commercially to:
A. Hasten ripening of fruits and promote female flowers in cucumbers ✓ Correct
B. Promote rooting
C. Cause bolting
D. Break dormancy of buds
Solution: Ethephon (releases ethylene) ripens fruits, promotes flowering in pineapple and female flowers in cucurbits.
Q5 — Abscisic Acid & Ethylene · hard · theory
ABA is also called the ______ because it promotes abscission and the ______ (dormancy of buds/seeds before winter):
A. Florigen; flowering
B. Dormin; dormancy ✓ Correct
C. Wound hormone; healing
D. Ripening hormone; ripening
Solution: ABA was earlier called "dormin" for its role in inducing bud and seed dormancy and promoting abscission.
Q6 — Abscisic Acid & Ethylene · hard · theory
Ethylene promotes rapid internode/petiole elongation in deep-water rice plants, allowing leaves to stay above water; this is because ethylene:
A. Enhances the elongation of submerged internodes ✓ Correct
B. Inhibits all growth
C. Closes stomata
D. Causes seed dormancy
Solution: In deep-water rice, ethylene stimulates internode elongation so the plant grows out of rising water (an exception to its usual growth-inhibiting/thickening effect).