Osmium tetroxide is used to fix or stain which tissue component?

Osmium tetroxide is used to fix or stain which tissue component?

• A. Proteins
• B. Lipids
• C. Nucleic Acids
• D. Carbohydrates

Answer: (B)

Osmium tetroxide targets lipids because it reacts with the carbon–carbon double bonds found in unsaturated fatty acids, especially those in phospholipid membranes. This reaction both fixes the lipids (stabilizing them during processing) and stains them with heavy osmium, making membranes highly electron-dense and visible under electron microscopy. This lipid-specific action gives excellent contrast for structures like cell membranes and myelin. It’s much less effective for fixing or staining proteins, nucleic acids, or carbohydrates, which require different reagents. So the tissue component best fixed or stained by osmium tetroxide is lipids.

Osmium tetroxide targets lipids because it reacts with the carbon–carbon double bonds found in unsaturated fatty acids, especially those in phospholipid membranes. This reaction both fixes the lipids (stabilizing them during processing) and stains them with heavy osmium, making membranes highly electron-dense and visible under electron microscopy. This lipid-specific action gives excellent contrast for structures like cell membranes and myelin. It’s much less effective for fixing or staining proteins, nucleic acids, or carbohydrates, which require different reagents. So the tissue component best fixed or stained by osmium tetroxide is lipids.