Biology Biomolecules SZABMU 2024 Reconduct
PMDC Verified Question 32 of 142
Lipids that protect plants from water loss are:
A
Phospholipids
B
Waxes
C
Terpenoid
D
Triglyceride
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option B: Waxes
Concept:

Terrestrial plants face the constant threat of desiccation (drying out) from the sun, requiring extreme external waterproofing.

Solution:

  • Plants secrete a highly hydrophobic, solid, protective lipid layer over their exposed epidermis (leaves, stems, fruits).


  • This specific layer is composed entirely of Waxes (specifically forming the cuticle, utilizing a wax polymer called cutin).


  • Because waxes are formed from extreme long-chain fatty acids and long-chain alcohols, they are completely insoluble in water and form a rigid, impermeable barrier that traps vital moisture inside the plant.


Why other options are incorrect:

  • Phospholipids: Used strictly for internal cell membranes, not massive external waterproofing.


  • Triglycerides: Used internally for energy storage (e.g., in seeds like peanuts), not on the surface.


  • Terpenoids: Used for internal pigments and fragrant volatile oils, not bulk structural waterproofing.

Quality & Fidelity Assurance: Every question on BeambePrep is rigorously curated against the official PMDC syllabus with zero filler, zero out-of-syllabus content, and zero typos. When an authentic past paper originally contained a historical mistake or ambiguity from the examining board (such as UHS or NUMS), BeambePrep faithfully reflects the original paper while detailing the nuance and scientific consensus in the autopsy above.

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