MICROANATOMY

Detailed explanation-1: -The plasma membrane is not impermeable to urea since it is a non-polar and uncharged molecule that can mix well well with phospholipids as well. The plasma membrane is selectively permeable and doesn’t allow the passage of charged and polar molecules via diffusion.

Detailed explanation-2: -Reason: Cell membrane is made up of a lipid bilayer. It is negative in charge due to the presence of polar heads of the lipid molecules. Glucose-6-phosphate also bears a negative charge in the form of the phosphate group. That’s why it is impermeable to the cell membrane.

Detailed explanation-3: -Small uncharged molecules can diffuse freely through a phospholipid bilayer. However, the bilayer is impermeable to larger polar molecules (such as glucose and amino acids) and to ions.