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.
General Knowledge
Biology
Difficulty: Easy
Choose an option
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ALipids and proteins are the major components; carbohydrates are minor and occur as oligosaccharide chains on the external surface (glycoproteins/glycolipids)
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BCarbohydrates form a continuous inner layer beneath lipids
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CProteins are absent; membranes are pure lipid
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DCarbohydrates freely flip-flop across both leaflets equally
Answer
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.
EliminationOptions claiming no proteins or inner carbohydrate layers are inconsistent with the model.
Final AnswerLipids + proteins major; carbohydrates as external glycans.