80. Which one of the following statements is FALSE with respect to phospholipids?
(A) Phospholipids have amphipathic character
(B) Phospholipids form the lipid bilayer of the cell membrane
(C) Phospholipids form micelles in living systems
(D) Some phospholipid molecules may contain a double bond in hydrophobic tails

This article breaks down a common biology MCQ on phospholipids, identifying the false statement with detailed explanations for each option. Perfect for students preparing for exams in biochemistry, cell biology, or molecular sciences.

Correct Answer: (C) Phospholipids form micelles in living systems

Why is (C) false?
Phospholipids do not form micelles in living systems. Micelles arise when single-tailed amphipathic molecules, like detergents or fatty acids, self-assemble in aqueous environments with their hydrophobic tails shielded inside and hydrophilic heads exposed. Phospholipids, however, have two hydrophobic fatty acid tails, making them too bulky for micelle formation. In cells, they spontaneously form bilayers instead, creating stable sheet-like structures ideal for membranes. Micelles might form in artificial lab conditions with specific phospholipid types under high curvature stress, but this doesn’t occur in vivo.

Explanation of All Options

(A) Phospholipids have amphipathic character
True. Phospholipids consist of a hydrophilic (water-loving) phosphate head group and two hydrophobic (water-repelling) fatty acid tails. This amphipathic nature drives their self-assembly into organized structures like bilayers, essential for compartmentalizing cellular processes.

(B) Phospholipids form the lipid bilayer of the cell membrane
True. In the fluid mosaic model of cell membranes, phospholipids arrange into a bilayer with hydrophilic heads facing the aqueous cytoplasm and extracellular space, while hydrophobic tails cluster in the core. This bilayer provides a semi-permeable barrier, embedding proteins and cholesterol for membrane function.

(C) Phospholipids form micelles in living systems
False (correct choice). As explained, the dual tails prevent micelle formation in biological contexts. Living systems favor bilayers for flat, expansive membranes, unlike spherical micelles suited for single-tailed lipids.

(D) Some phospholipid molecules may contain a double bond in hydrophobic tails
True. Phospholipids like phosphatidylcholine can have unsaturated fatty acids (e.g., oleic acid with one double bond) in their tails. These double bonds introduce kinks, lowering the melting point, increasing membrane fluidity, and aiding function at physiological temperatures.

Why This Matters for Biology Students

Understanding phospholipid behavior clarifies membrane structure, transport, and signaling—key topics in exams like NEET, CSIR NET, or university biochemistry courses. The false statement hinges on geometry: micelles for cone-shaped lipids, bilayers for cylindrical ones like phospholipids.

For more MCQs on phospholipids structure and function, check related topics like lipid bilayers or amphipathic molecules.