Biology Circulation / Transport SZABMU 2024
PMDC Verified Question 1 of 54
In the roots apoplast pathway becomes discontinuous in the endodermis due to the presence of:
A
Casparian strips
B
Pericycle
C
Stele
D
Pith
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option A: Casparian strips
Concept:

To control the uptake of water and minerals, plants force apoplastic flow to cross a selectively permeable cell membrane before entering the vascular cylinder.

Formula:

None

Solution:

  • Water traveling freely through the porous cell walls (the apoplast pathway) eventually reaches the endodermis, the innermost layer of the root cortex.


  • The radial and transverse walls of the endodermal cells contain a waxy, hydrophobic band called the Casparian strip (made of suberin).


  • This strip acts as a waterproof dam, forcing water to detour into the living cytoplasm (symplast) to be biologically filtered.


Why other options are incorrect:

  • Pericycle / Stele: These are tissues located deeper inside the root, past the endodermal checkpoint.

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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