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Plant hormones and responses (tropisms)

Biology • Plants • Knowledge-Based • 5 questions

Plant hormones and responses (tropisms) Knowledge-Based Download PDF

Biology · Diversity of Life · Biology · Plants

5 Biology practice questions on Plant hormones and responses (tropisms). Questions that assess core concepts and understanding.

Questions

  1. 1.

    Which gaseous plant hormone plays a central role in stimulating commercial fruit ripening and promoting leaf abscission in deciduous plants?

    • A) Ethylene
    • B) Gibberellin
    • C) Cytokinin
    • D) Auxin
  2. 2.

    Which plant hormone rapidly accumulates in leaves during periods of water deficit to trigger stomatal closure and reduce transpirational water loss?

    • A) Auxin
    • B) Cytokinin
    • C) Gibberellin
    • D) Abscisic acid
  3. 3.

    In climbing plants, contact with a physical object stimulates tendrils to coil tightly around the structure. Which mechanism directly accounts for this positive thigmotropic curvature?

    • A) Accelerated cell division on the inner contact surface while the outer surface undergoes programmed cell death
    • B) Inhibited elongation of cells on the outer surface combined with increased turgor pressure on the contact side
    • C) Symmetrical cell elongation on both sides followed by sudden dehydration of the touching surface
    • D) Greater elongation of cells on the outer, non-contact side compared to cells on the inner, contact side
  4. 4.

    When a germinating root is oriented horizontally, auxin accumulates along its lower side. How does this uneven distribution of auxin lead to positive gravitropism in the root?

    • A) It stimulates rapid cell elongation on the lower side, bending the root tip upward away from the soil.
    • B) It accelerates localized cell division in the root cap, mechanically driving the root tip directly downward.
    • C) It inhibits cellular respiration on the lower surface, inducing a localized wilting response that droops downward.
    • D) It inhibits cell elongation on the lower side, allowing faster elongation on the upper side to curve the root downward.
  5. 5.

    Which plant hormone accumulates on the shaded side of a growing shoot tip to stimulate cell elongation and cause positive phototropism?

    • A) Ethylene
    • B) Abscisic acid
    • C) Cytokinin
    • D) Auxin