Membranes are Differentially Permeable

Membranes are Differentially Permeable - Membranes are...

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Membranes are Differentially Permeable The plasma membrane is differentially permeable because some particles can pass through, others cannot. It can control the extent to which certain substances pass through. Nonpolar molecules pass through cell membranes more readily than polar molecules because the center of the lipid bilayer (the fatty acid tails) is nonpolar and does not readily interact with polar molecules. The following substances can pass through the cell membrane: Nonpolar molecules (example: lipids) Small polar molecules such as water The following substances cannot pass through the cell membrane: Ions and charged molecules (example: salts dissolved in water) Large polar molecules (example: glucose) Macromolecules Osmosis Osmosis is the diffusion of water across a differentially permeable membrane (see " Diffusion " above). It occurs when a solute (example: salt, sugar, protein, etc.) cannot pass through a membrane but the solvent (water) can pass through. In areas where the solute concentration is high, the
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Membranes are Differentially Permeable - Membranes are...

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