Membrane Transport Mechanisms · Physiology

Which of the following is a major limitation of passive diffusion across the cell membrane for maintaining homeostasis in typical mammalian cells?

  1. Passive diffusion is far too energy intensive for cells
  2. Passive diffusion cannot move ions or polar molecules efficiently
  3. Passive diffusion requires carrier proteins which can saturate
  4. Passive diffusion always moves substances against their gradients
Show answer and explanation

Correct answer: Passive diffusion cannot move ions or polar molecules efficiently

Because the lipid bilayer is hydrophobic, passive diffusion cannot efficiently move ions or polar molecules across the membrane; these require specialized transport proteins or active processes to maintain cellular homeostasis.

Difficulty: Medium Question 20 of 24

Practice all 24 Membrane Transport Mechanisms questions

Keep practicing

More Membrane Transport Mechanisms questions