NEET (UG) · Botany, Class 11
Plant Growth and Development: NEET PYQ, 2018–2026
Plant Growth and Development (Botany, Class 11) has been asked 20 times in the 7 NEET papers from 2018, 2020, 2021, 2023, 2024, 2025 and 2026: about 2.9 questions a paper, 6% of all Botany questions. It is the 8th most-asked of 17 Botany chapters. NEET 2026 had 3 from it. Last checked 28 October 2026.
Questions per paper
Year by year.
| Year | Questions |
|---|---|
| 2018 | 0 |
| 2020 | 3 |
| 2021 | 4 |
| 2023 | 3 |
| 2024 | 5 |
| 2025 | 2 |
| 2026 | 3 |
From 2021 to 2024 each paper had 200 questions (a Section B with a choice); the others had 180.
Inside the chapter
Topics asked most.
- Plant hormones10
- Seed germination and differentiation7
- Growth phases2
- Photoperiodism1
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10 Plant Growth and Development questions to practise.
Our own questions, written in the NEET pattern and checked, each with an explanation. Pick an option to see the answer.
Q1 · Botany · Plant Growth and Development
A tomato grower sprays unpollinated tomato flowers with an auxin solution and obtains seedless fruits. Which process does the auxin most directly stimulate in these fruits?
Answer: (A)
Principle: auxins such as IAA and NAA promote cell enlargement and fruit growth. When fertilisation is prevented, the ovary can still develop into a fruit if auxin is supplied, and the fruit is seedless. The question asks which process the auxin stimulates, and the answer is parthenocarpy. The distractors each reflect a mix-up between auxin and another hormone: ethylene and abscission, gibberellin and dormancy, or abscisic acid and stomatal closure.
Q2 · Botany · Plant Growth and Development
On a sigmoid growth curve of a cell population, with cell number plotted against time, at which point is the growth rate (the slope of the curve) greatest?
Answer: (A)
Growth rate is the rate of change of population size, which on a graph of number against time is the slope. A sigmoid curve starts flat, becomes steep, and then flattens again. The steepest point, the inflection point, lies in the middle of the log phase, where the growth rate is maximal. The size of the population at a point and its growth rate at that point are different quantities.
Q3 · Botany · Plant Growth and Development
The number of cells in a bacterial-like culture is 200 at t = 2 h and 3200 at t = 6 h, and the culture grows geometrically following W = W₀e^(rt), where t is in hours. What is the value of the growth constant r?
Answer: (B)
From W = W₀e^(rt), the ratio of two counts depends only on the time difference: W₂/W₁ = e^(r(t₂−t₁)). Here W₂/W₁ = 3200/200 = 16 and t₂−t₁ = 4 h, so e^(4r) = 16. Taking the natural logarithm gives 4r = ln 16 ≈ 2.773, so r ≈ 0.693 per hour. Students should check that the logarithm base matches the base of the exponential and that they divide by the actual time interval, not the starting or final time. This is standard geometric growth reasoning from NCERT Class 11.
Q4 · Botany · Plant Growth and Development
Which plant growth regulator stimulates the synthesis of hydrolytic enzymes such as alpha-amylase in the aleurone layer of germinating cereal grains?
Answer: (A)
Principle: during germination, gibberellin from the embryo acts on the aleurone layer and triggers synthesis of hydrolytic enzymes such as alpha-amylase. These digest the stored starch in the endosperm into sugars for the growing embryo. Apply: the hormone that induces this enzyme synthesis is gibberellin. ABA opposes it, which is why ABA is a distractor.
Q5 · Botany · Plant Growth and Development
In a seedling that undergoes hypogeal germination, which part elongates to push the plumule above the soil while the cotyledons remain below ground?
Answer: (A)
Principle: germination patterns differ by where the cotyledons end up. In epigeal germination the hypocotyl elongates, arching the cotyledons and plumule above the soil. In hypogeal germination the cotyledons stay underground while the epicotyl elongates and lifts the plumule. Pea and gram show hypogeal germination, while castor and bean show epigeal germination. Apply the rule: identify whether the cotyledons leave the soil, and the elongating axis follows directly.
Q6 · Botany · Plant Growth and Development
Leaf discs of identical size are cut from one healthy leaf. One set is floated on water and the other on a cytokinin solution, both kept in continuous darkness for 72 hours. The water-floated discs turn yellow, while the cytokinin-treated discs stay green. Which conclusion best explains this result?
Answer: (B)
Senescence in detached leaves is driven by the loss of chlorophyll and proteins. Cytokinins slow this loss by preserving protein synthesis and membrane integrity, which keeps the green colour. Water-floated discs have no cytokinin supply and therefore senesce in darkness. The distractors either invent a light-independent role for cytokinin, reverse the roles of cytokinin and ethylene, or invent a metabolic conversion that does not occur.
Q7 · Botany · Plant Growth and Development
In the germinating grain of maize, what is the name of the single large cotyledon that absorbs digested food from the endosperm and transfers it to the growing embryo?
Answer: (A)
The maize embryo has one cotyledon, called the scutellum, which lies against the endosperm. It absorbs digested food released by the aleurone and transfers it to the growing embryo. The coleoptile and coleorhiza are protective sheaths, and the epiblast is a minor structure, so none of them absorbs food.
Q8 · Botany · Plant Growth and Development
In cereal grains such as barley, the embryo releases a hormone into the aleurone layer during germination. Which change does this hormone trigger in the aleurone layer?
Answer: (A)
In cereals, the embryo produces gibberellin, which diffuses to the aleurone layer and triggers synthesis of alpha-amylase and other hydrolases. These enzymes break down starch and proteins in the endosperm, providing nutrients to the embryo. The question tests the specific response, not just the general role of GA.
Q9 · Botany · Plant Growth and Development
In a sigmoid (S-shaped) growth curve of a plant or cell population under limited resources, at which point is the absolute growth rate (change in number per unit time) highest?
Answer: (C)
Absolute growth rate is the change in population per unit time, which is the slope of the growth curve. In the sigmoid curve, slope rises from near zero in the lag phase, becomes steepest at the inflection point where the population is about half the carrying capacity, and then flattens as resources limit growth. Students should separate the size of the population from the rate at which it changes, and should not assume the fastest change happens at the largest or first measured value. NCERT Class 11 treats growth in terms of phases and resource limits, and the mathematical framing here is a direct extension of that.
Q10 · Botany · Plant Growth and Development
Bananas harvested while green are kept in a closed room with a source of ethylene gas, and they ripen quickly. What is the main effect of ethylene in this situation?
Answer: (A)
Principle: ethylene is a gaseous hormone that promotes fruit ripening. In climacteric fruits like banana, it triggers a rise in respiration and changes in texture and colour. Storing green bananas with ethylene or ripe fruit speeds this up. Here the ethylene acts on the fruit, not on plant height or cell division, so the answer is accelerated ripening.
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All 20 real NEET questions from Plant Growth and Development.
The questions from the actual papers, with the official answer and an explanation for each — chapter by chapter, or as full timed papers.
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About Plant Growth and Development in NEET.
How many questions come from Plant Growth and Development in NEET?
Plant Growth and Development (Botany, Class 11) has been asked 20 times in the 7 NEET papers from 2018, 2020, 2021, 2023, 2024, 2025 and 2026: about 2.9 questions a paper, 6% of all Botany questions. It is the 8th most-asked of 17 Botany chapters. NEET 2026 had 3 from it.
Which topics of Plant Growth and Development are asked most in NEET?
Plant hormones (10), Seed germination and differentiation (7), Growth phases (2), Photoperiodism (1), counted over the papers from 2018–2026.
Is Plant Growth and Development important for NEET 2027?
It is in the syllabus in force, so it can be asked. By past papers it ranks 8 of 17 in Botany; use that to decide how much time it gets, not whether to study it.
Where can I solve Plant Growth and Development NEET previous year questions?
On Nikaalle, free: sign up and practise every past NEET question from Plant Growth and Development with an explanation for each, or sit the full papers timed. The ten questions on this page are our own, written in the same pattern.
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