Cell membranes are: A. always impermeable to small molecules B. always permeable to charged atoms and molecules C. differentially permeable D. impermeable to all atoms and molecules

Cell membranes are:
A. always impermeable to small molecules
B. always permeable to charged atoms and molecules
C. differentially permeable
D. impermeable to all atoms and molecules

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Answer

• differentially permeable
  Explanation:
  Cell membranes allow entry and exit of molecules and atoms at different locations and in different rates determined by the properties of the molecules. Cell membranes do not allow entry of charged molecules and atoms through simple diffusion. Therefore, cell membrane is differentially permeable allowing some molecules to pass through more easily than others.