Top 20 MCQs on Plant Physiology, Anatomy & Photosynthesis for Competitive Exams

  1. Which pigment is responsible for the red, orange, and yellow coloration in leaves?
    (A) Aldehydes
    (B) Tannins
    (C) Lignins
    (D) Carotenoids
    Ans: (D) Carotenoids
  2. In which part of the cabbage plant is food stored?
    (A) Leaves
    (B) Stem
    (C) Fruit
    (D) Scurvy
    Ans: (A) Leaves
  3. What is the primary biological process through which plants reproduce?
    (A) Pollination
    (B) Condensation
    (C) Consumption
    (D) Evaporation
    Ans: (A) Pollination
  4. Plants that grow optimally in bright sunlight are known as:
    (A) Sciophilous
    (B) Xerophytes
    (C) Heliophytes
    (D) Epiphytes
    Ans: (C) Heliophytes
  5. Which plant hormone is mainly responsible for maintaining seed dormancy?
    (A) Abscisic Acid
    (B) Gibberellic Acid
    (C) Indole Acetic Acid
    (D) Ethylene
    Ans: (A) Abscisic Acid
  6. A fruit that develops from a multicarpellary apocarpous gynoecium is called:
    (A) Composite
    (B) Aggregate
    (C) Simple
    (D) Multiple
    Ans: (B) Aggregate
  7. What is the term for the winter dormancy period in animals?
    (A) Aestivation
    (B) Hibernation
    (C) Regeneration
    (D) Mutation
    Ans: (B) Hibernation
  8. Which of the following acts as the substrate in photorespiration?
    (A) Fructose
    (B) Pyruvic Acid
    (C) Glycolate
    (D) Glucose
    Ans: (C) Glycolate
  9. What is the first stable product formed during photosynthesis?
    (A) Starch
    (B) Sucrose
    (C) Phosphoglyceric Acid (PGA)
    (D) Glucose
    Ans: (C) Phosphoglyceric Acid (PGA)
  10. In which plant are dumb-bell-shaped guard cells found?
    (A) Groundnut
    (B) Gram
    (C) Wheat
    (D) Mango
    Ans: (C) Wheat
  11. How do plants release excess absorbed water?
    (A) Evaporation
    (B) Osmosis
    (C) Diffusion
    (D) Transpiration
    Ans: (D) Transpiration
  12. What physical force primarily enables roots to absorb water?
    (A) Elasticity
    (B) Capillarity
    (C) Viscosity
    (D) Photosynthesis
    Ans: (B) Capillarity
  13. Which plant part is mainly responsible for transpiration?
    (A) Stem
    (B) Leaves
    (C) Roots
    (D) All aerial parts
    Ans: (B) Leaves
  14. The corners of collenchyma cells thicken due to deposition of:
    (A) Lignin and Suberin
    (B) Suberin and Cutin
    (C) Cellulose and Pectin
    (D) Chitin and Lignin
    Ans: (C) Cellulose and Pectin
  15. The sudden folding of leaves in the “Touch-me-not” plant is an example of:
    (A) Photonasty
    (B) Nyctinasty
    (C) Seismonasty
    (D) Chemonasty
    Ans: (C) Seismonasty
  16. Kidney-shaped guard cells are typically seen in:
    (A) Dicot Plants
    (B) Monocot Plants
    (C) Both A and B
    (D) Algae
    Ans: (A) Dicot Plants
  17. In cacti, the spines are modified forms of:
    (A) Stems
    (B) Stipules
    (C) Leaves
    (D) Buds
    Ans: (C) Leaves
  18. What causes the stomata to open?
    (A) Exosmosis
    (B) Endosmosis
    (C) Plasmolysis
    (D) Low Cell Sap Concentration
    Ans: (B) Endosmosis
  19. 2,4-D is widely used as a:
    (A) Weedicide
    (B) Vitamin
    (C) Fertilizer
    (D) Insecticide
    Ans: (A) Weedicide
  20. The liquid inside a coconut is actually:
    (A) Liquid Nucellus
    (B) Liquid Mesocarp
    (C) Liquid Endocarp
    (D) Degenerated Liquid Endosperm
    Ans: (D) Degenerated Liquid Endosperm

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