Biology Respiration / Gaseous Exchange UHS 2022
PMDC Verified Question 12 of 34
The respiratory surfaces exhibit following characteristic:
A
It must be thick for low diffusion
B
It must be permeable
C
It should be non-vascularized
D
It should have low ventilation mechanism
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option B: It must be permeable
Concept: For a respiratory surface to be efficient, it must maximize the rate of diffusion as described by Fick's Law.

Solution:
  • An ideal respiratory surface must have several key traits: large surface area, highly vascularized network, extremely thin walls, and high permeability to gases.
  • Permeability allows \( \text{O}_2 \) and \( \text{CO}_2 \) to dissolve and effortlessly cross the cell membranes.


Why other options are incorrect:
  • Thick for low diffusion: A thick surface severely impedes diffusion; it must be microscopically thin.
  • Non-vascularized: Lack of blood supply means gases cannot be transported away, halting the concentration gradient.
  • Low ventilation: High ventilation is strictly required to bring in fresh air and maintain steep partial pressure gradients.

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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