Question

Which of these molecules require a carrier protein to pass through the cell membrane?

(a) Small neutral solutes

(b) Water

(c) Polar molecules

(d) Non – polar molecules

This question was addressed to me in a job interview.

Question is from Eukaryotic Cells and it’s Organelles in chapter Cell : The Unit of Life of Biology – Class 11

Answer 1

Right answer is (c) Polar molecules

Explanation: Since the cell membrane is a phospholipid bilayer having non – polar lipid tail groups, polar molecules cannot pass through the membrane without the assistance of carrier proteins present within the membrane.