Question

Identify correct sentence(s) regarding membrane lipids:
(A). Membrane lipids are amphipathic
(B). Membrane lipids forms bilayers
(C). Membrane lipids are polar
(D). Membrane lipids forms single layer
Choose the correct answer from the options given below:

• A. (A), (B) and (C) only.
• B. (A) and (B) only.
• C. (A), (B), (C) and (D).
• D. (B), (C) and (D) only.

Hint:

The key to membrane structure is the "lipid bilayer."
Any statement suggesting that cell membranes are formed of single lipid layers is structurally incorrect and can be discarded.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
Membrane lipids, including phospholipids, glycolipids, and sterols, are the structural basis of biological membranes.
Their chemical structure determines how they assemble into functional cell boundaries.

Step 2: Detailed Explanation:
- Amphipathic nature (A): Membrane lipids possess both a hydrophilic (polar, water-loving) head group and a hydrophobic (non-polar, water-fearing) hydrocarbon tail.
- Bilayer formation (B): In an aqueous environment, these lipids spontaneously organize into a bilayer, shielding the hydrophobic tails inside while exposing the hydrophilic heads to the water on both sides.
- Polarity (C): They are polar molecules due to the charged or polar groups present in their hydrophilic heads (such as phosphate or sugar groups).
- Single-layer formation (D): Biological membranes are always double-layered (bilayers), not single layers, as a single layer would expose hydrophobic tails to water on one side.
Therefore, statements (A), (B), and (C) are correct.

Step 3: Final Answer:
The correct answer is (A), (B) and (C) only, corresponding to option (A).