Biology Cell NUMS 2024
PMDC Verified Question 7 of 143
Which one is the function of plasma membrane proteins?
A
Prevention of freezing during cold weather
B
Restrict entry of polar molecules
C
Movement of ions in and out of the cell
D
Maintenance of membrane flexibility
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option C: Movement of ions in and out of the cell
Concept: Ions cannot cross the hydrophobic lipid bilayer on their own and require specialized tunnels.

Solution: A primary function of integral plasma membrane proteins is to act as channels, carriers, and pumps to facilitate the movement of ions (like $\text{Na}^+$, $\text{K}^+$, $\text{Ca}^{2+}$) in and out of the cell.

Distractor Autopsy:
  • Restricting polar molecules: Function of the lipid bilayer.
  • Flexibility/Freezing prevention: Function of unsaturated fatty acid tails and cholesterol.

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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