Cell membrane overview: Which statement best summarizes core properties and functions of biological membranes in cells and organelles?

Introduction / Context:
Biological membranes underlie cellular compartmentalization, homeostasis, and communication. Their composition and structure explain how cells create specialized environments and regulate exchanges with precision.

Given Data / Assumptions:

• Membranes are lipid bilayers embedded with proteins and decorated with carbohydrates.
• They delimit the cell surface and various organelles (e.g., mitochondria, ER, nucleus).
• They confer selective permeability and host receptors, channels, and transporters.

Concept / Approach:
The fluid mosaic model captures membranes as dynamic bilayers with heterogeneous protein content. Carbohydrates (glycolipids, glycoproteins) contribute to cell recognition and protection. All listed statements describe these properties, so the inclusive option is correct.

Step-by-Step Solution:

Verification / Alternative check:
Textbook descriptions of plasma membranes and organelle membranes consistently affirm these roles and compositions, reinforcing the “all of the above” choice.

Why Other Options Are Wrong:

• Any single statement alone is incomplete; membranes fulfill multiple simultaneous functions.
• “None of these” contradicts core cell biology.

Common Pitfalls:
Overlooking the diversity of membrane protein content among organelles (e.g., myelin vs. inner mitochondrial membrane) and the functional consequences of that diversity.

Final Answer:
All of the above