Biology Homeostasis PMDC Conceptual Practice
PMDC Verified Question 58 of 99
The thick ascending limb of the loop of Henle actively transports \(\text{Na}^+\) and \(\text{Cl}^-\), but is completely impermeable to:
A
Water
B
\(\text{Na}^+\) ions
C
\(\text{K}^+\) ions
D
\(\text{Cl}^-\)- ions
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option A: Water
Concept: Segmental tubular permeability.

Solution: The thick ascending limb lacks aquaporin channels, making it impermeable to water. Active reabsorption of salts without water dilution creates hypotonic tubular fluid.

Why other options are incorrect:
  • Option B, Option C & Option D: The ascending limb actively transports \(\text{Na}^+\), \(\text{K}^+\), and \(\text{Cl}^-\) ions across luminal membranes via NKCC2 cotransporters.

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.

Previous Question All Homeostasis MCQs Next Question

Want to solve full-length papers under timed exam conditions?

Practice with zero-scroll lockdown sprints, dynamic latency zone timers, live peer selection telemetry, and the automated Amber mistake recovery loop.

Enter Arena Sprint iOS App Android App