Which statement about phospholipids is not true?

Which statement about phospholipids is not true?

• A. I
• B. II
• C. III
• D. IV

Answer: (B)

Phospholipids are amphipathic molecules with a glycerol backbone, two fatty acid tails, and a phosphate-containing head group. This arrangement gives them a polar, hydrophilic head and nonpolar, hydrophobic tails, so they naturally align at water interfaces and form membranes. Because of this structure, their main role is in building and maintaining cell membranes, not in storing energy. The bilayer arrangement creates a hydrophobic interior that blocks most water-soluble substances, while the hydrophilic heads face the aqueous environments on each side of the membrane. The fatty acid tails can be saturated or unsaturated, which affects membrane fluidity, and other components like cholesterol help tune that fluidity. A statement about phospholipids that isn’t true would be one that contradicts these points—for example, claiming they are primarily energy storage molecules (that role belongs to triglycerides), or that they lack a glycerol backbone, or that their head groups are nonpolar. Since the answer indicates the incorrect choice, it would be the statement that clashes with these fundamental properties.

Phospholipids are amphipathic molecules with a glycerol backbone, two fatty acid tails, and a phosphate-containing head group. This arrangement gives them a polar, hydrophilic head and nonpolar, hydrophobic tails, so they naturally align at water interfaces and form membranes. Because of this structure, their main role is in building and maintaining cell membranes, not in storing energy. The bilayer arrangement creates a hydrophobic interior that blocks most water-soluble substances, while the hydrophilic heads face the aqueous environments on each side of the membrane. The fatty acid tails can be saturated or unsaturated, which affects membrane fluidity, and other components like cholesterol help tune that fluidity.

A statement about phospholipids that isn’t true would be one that contradicts these points—for example, claiming they are primarily energy storage molecules (that role belongs to triglycerides), or that they lack a glycerol backbone, or that their head groups are nonpolar. Since the answer indicates the incorrect choice, it would be the statement that clashes with these fundamental properties.