Classes of membrane lipids Which of the following lipid classes are found in cellular membranes?
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AGlycerophospholipids
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BSphingolipids
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CSterols (for example, cholesterol)
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DAll of these
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ETriglycerides only
Answer
Correct Answer: All of these
Explanation
Introduction / Context:Membrane architecture relies on a mixture of amphipathic lipids. Recognizing the principal classes helps explain curvature, signaling, and raft formation.
Given Data / Assumptions:
- Phospholipids (glycerophospholipids) are the dominant bilayer constituents.
- Sphingolipids contribute to microdomains and recognition (for example, sphingomyelin, glycosphingolipids).
- Sterols (cholesterol) modulate fluidity and permeability in eukaryotes.
Concept / Approach:All three classes co-exist in many eukaryotic membranes, with proportions varying by organelle and organism. Their combined properties generate membrane order, thickness, and platforms for protein function.
Step-by-Step Solution:List known membrane lipids: glycerophospholipids, sphingolipids, sterols.Confirm they are amphipathic and assemble into bilayers.Select the inclusive option “All of these.”
Verification / Alternative check:Analytical lipidomics of plasma membranes consistently identifies all three classes.
Why Other Options Are Wrong:
- Single-class answers: Incomplete view of real membranes.
- Triglycerides only: Triacylglycerols are storage lipids, not bilayer-forming membrane staples.
Common Pitfalls:Assuming one lipid type explains all membrane behavior; composition is heterogeneous and dynamic.
Final Answer:All of these.