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What is wrong about the description of cell membrane structure and function ( ) A. Cell membrane is

更新时间:2026-06-14 15:00:37   栏目: 中华词典

What is wrong about the description of cell membrane structure and function ( ) A. Cell membrane is a semi-permeable membrane with special structure and function B. Cell membranes are the gateway for cells to be affected by other factors C. The structure of the cell membrane is based on a lipid bilayer and is embedded with proteins with different physiological functions. D. Water-soluble substances generally pass freely through the cell membrane, while fat-soluble substances cannot

The incorrect description is option D. The cell membrane's permeability follows the opposite pattern: fat-soluble substances typically pass freely through the lipid bilayer, while water-soluble substances face restrictions and often require protein transporters.

Let’s analyze each option:

Option A correctly states that the cell membrane is semi-permeable. This property allows selective passage of molecules (e.g., oxygen, carbon dioxide) while blocking others (e.g., large polar molecules like glucose), supported by its phospholipid bilayer structure.

Option B is accurate because cell membranes contain receptors (e.g., for hormones, neurotransmitters) that enable cells to respond to external signals. This "gateway" function is critical for cell communication and homeostasis.

Option C describes the fluid mosaic model, the universally accepted structure of cell membranes. Phospholipids form the bilayer, and embedded proteins perform diverse roles (transport, signaling, enzymatic activity).

Option D reverses the actual permeability. The lipid bilayer’s hydrophobic core allows fat-soluble (nonpolar) substances (e.g., steroids, oxygen) to diffuse freely, while water-soluble (polar) molecules (e.g., ions, glucose) generally cannot pass without protein assistance.

Understanding membrane permeability is foundational to cellular biology, as it explains how cells maintain internal environments distinct from their surroundings. How might disruptions in this permeability affect cellular function?

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