NEET (UG)

Practice Test 1 — Plant Growth and Development

12 questions • 18 minutes • auto-graded with full solutions

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Section A — MCQ (Single Correct)

Question 1

The correct sequence of growth phases at a root tip is:

Solution: Meristematic → elongation → maturation.

Question 2

The sigmoid growth curve is typical of:

Solution: Geometric growth gives the sigmoid (S-shaped) curve.

Question 3

Formation of cork cambium from parenchyma is an example of:

Solution: Mature cells regain division — dedifferentiation.

Question 4

Which hormone is used to induce rooting in stem cuttings?

Solution: Auxins promote root initiation in cuttings.

Question 5

Fruit ripening is promoted by:

Solution: Ethylene promotes fruit ripening.

Question 6

Closure of stomata during water stress is brought about by:

Solution: ABA (stress hormone) closes stomata.

Question 7

Chrysanthemum, which flowers in short days, is a:

Solution: Chrysanthemum is a short-day plant.

Question 8

Vernalisation is the promotion of flowering by:

Solution: Vernalisation = cold-induced promotion of flowering.

Section B — Assertion & Reason

Question 9

A: Removing the shoot apex promotes the growth of lateral branches.
R: The shoot apex is the source of auxin, which maintains apical dominance over the lateral buds.

Solution: Removing the auxin source releases the lateral buds — R explains A.

Question 10

A: Abscisic acid helps plants survive drought.
R: ABA induces closure of stomata, reducing water loss.

Solution: Stomatal closure conserving water is how ABA helps in drought — R explains A.

Question 11

A: In photoperiodism, the photoperiod is perceived by the shoot apex.
R: The leaves produce the flowering signal that moves to the shoot apex.

Solution: A is false — the LEAVES perceive the photoperiod (not the shoot apex); R correctly states the leaves produce the signal.

Question 12

A: Cytokinins can delay the ageing of detached leaves.
R: Cytokinins promote nutrient mobilisation and delay senescence (Richmond–Lang effect).

Solution: Delaying senescence is exactly why leaves stay green longer — R explains A.