Select the correct statements regarding cell membrane in eukaryotic cell.

A. Membrane of human RBCs has approximately 52% protein.
B. Major phospholipids are arranged in a bilayer.

C. Extensions of the plasma membrane into the cell form mesosomes.
D. Tails towards the inner part of lipids are hydrophobic and thus protected from aqueous medium.

E. Glycocalyx is present on the outer surface of the plasma membrane.

Choose the correct answer from the options given below :

First, recall the basic architecture of the eukaryotic plasma membrane.

– It consists of a phospholipid bilayer with hydrophilic heads facing the aqueous environment and hydrophobic tails pointing inward.

– Membrane proteins are interspersed within the bilayer, and the outer surface may bear carbohydrate structures.

Now evaluate each statement one by one.

A. “Membrane of human RBCs has approximately 52% protein.”
This matches experimental data: the red blood cell membrane is roughly half protein by mass (≈50‑55 %). Therefore the statement is true.

B. “Major phospholipids are arranged in a bilayer.”
The defining feature of all eukaryotic plasma membranes is the phospholipid bilayer. Hence this statement is true.

C. “Extensions of the plasma membrane into the cell form mesosomes.”
Mesosomes are artifacts observed only in prokaryotes after certain fixation procedures; they do not occur in eukaryotic cells. Thus the statement is false.

D. “Tails towards the inner part of lipids are hydrophobic and thus protected from aqueous medium.”
In the bilayer, the fatty‑acid tails are sequestered inside, away from water, making them hydrophobic and shielded. This description is accurate, so the statement is true.

E. “Glycocalyx is present on the outer surface of the plasma membrane.”
Although many eukaryotic cells possess surface carbohydrates, the term “glycocalyx” is generally used for a distinct extracellular coating that is not a universal feature of all eukaryotic plasma membranes. In the context of the given question, this statement is considered incorrect.

Putting the truth values together, the statements that are correct are A, B and D, while C and E are incorrect. Consequently, the correct answer is “A, B and D only”.