Cell membrane composition (fluid mosaic model): Considering proteins, lipids, and carbohydrates in a plasma membrane, which statement is true? Context: Bilayer structure with asymmetry and glycocalyx. Choose the correct statement.

Difficulty: Easy

Lipids and proteins are the major components; carbohydrates are minor and occur as oligosaccharide chains on the external surface (glycoproteins/glycolipids)
Carbohydrates form a continuous inner layer beneath lipids
Proteins are absent; membranes are pure lipid
Carbohydrates freely flip-flop across both leaflets equally

Correct Answer: Lipids and proteins are the major components; carbohydrates are minor and occur as oligosaccharide chains on the external surface (glycoproteins/glycolipids)

Explanation:

Concept / Approach (Fluid Mosaic)
The plasma membrane is a phospholipid bilayer with embedded/integral and peripheral proteins. Carbohydrates constitute a minor fraction and are present as glycoproteins and glycolipids on the extracellular face forming the glycocalyx; they are asymmetric and do not flip-flop freely.

Elimination
Options claiming no proteins or inner carbohydrate layers are inconsistent with the model.

Cell membrane composition (fluid mosaic model): Considering proteins, lipids, and carbohydrates in a plasma membrane, which statement is true? Context: Bilayer structure with asymmetry and glycocalyx. Choose the correct statement.

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