Biology Cell SZABMU 2023
PMDC Verified Question 47 of 143
Outer membrane of mitochondria and chloroplast resembles as both are:
A
Freely permeable to small molecules
B
Semipermeable
C
Freely permeable to large molecules
D
Impermeable
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option A: Freely permeable to small molecules
Concept: The outer boundary of endosymbiotic organelles is designed to allow easy access for cellular metabolites.

Solution: The outer membranes of both mitochondria and chloroplasts contain abundant transport proteins called porins. These create large aqueous channels making the outer membrane freely permeable to small molecules and ions.

Distractor Autopsy: The inner membrane is highly impermeable/semipermeable to strictly regulate proton gradients. Neither is permeable to very large macromolecules without specific translocators.

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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