Which would most likely pass unaided through a plasma membrane?
A)Something small and nonpolar, such as nitrogen gas
B)Something small and polar, such as a water molecule
C)Something small and charged, such as an ion
D)Something large, such as a glucose molecule

Question

Quizplus · Accepted Answer

Substances that are small and nonpolar, such as nitrogen gas, can pass unaided through a plasma membrane because they can dissolve in the hydrophobic interior of the membrane. Water molecules (B) are small and polar, but they cannot easily pass through the hydrophobic interior of the membrane. Small charged molecules (C) cannot easily pass through the hydrophobic interior of the membrane either. Large molecules such as glucose (D) require a transport protein to pass through the plasma membrane.

Which Would Most Likely Pass Unaided Through a Plasma Membrane