The term used to distinguish hydrophobic and hydrophilic lipids in the described technique is?

• A. OTAN
• B. Osmium tetroxide
• C. Borax ferrocyanide
• D. Isopropanol glycol

Answer: (A)

The key idea here is how lipid molecules differ in polarity and how a technique can separate or label lipids based on that polarity. In this method, the term used to distinguish between hydrophobic (nonpolar) and hydrophilic (polar) lipids is OTAN. The approach relies on differential affinity: hydrophobic lipids interact with nonpolar environments and tend to be solubilized or visualized differently from hydrophilic lipids, which prefer polar conditions. OTAN captures that polarity-based distinction, making it the best descriptor for separating or identifying lipid classes in this context.

Osmium tetroxide is mainly a fixative that preserves and stains unsaturated lipids for electron microscopy, not a descriptor of lipid polarity. Borax ferrocyanide is used in some staining steps but does not define the hydrophobic versus hydrophilic distinction. Isopropanol glycol is a solvent used in processing, not the term that labels lipid polarity in this technique.