Explanation:
-Cell membrane is a selectively permeable membrane which is made up of phospholipid arranged in a bilayer.
-Therefore it allows lipid soluble or hydrophobic molecules and gases like oxygen and carbon dioxide to diffuse through the membrane rapidly.
-Ethanol which is a polar molecule can also cross the membrane but at a slow rate.
-On the other hand cell membrane restricts the entry of highly charged molecules like some ions, sugars and amino acids (they require special transport proteins).
Answer:
Allowed to pass:
Water molecules
O2
CO2
Ethanol
Kept out:
Some ions
Sugars
Amino acids
