Steroids are what type of compound?

• A. Protein
• B. Lipid
• C. Carbohydrate
• D. Vitamin

Answer: (B)

Steroids are a type of lipid because they share the chemical nature and properties that define lipids: they are nonpolar, largely insoluble in water, and built on a four-ring carbon skeleton. This steroid framework distinguishes them from other organic classes. Proteins are made of amino acids linked by peptide bonds, and carbohydrates are built from sugar units with many hydroxyl groups—neither describes steroids. Some compounds later used as vitamins are not steroids by definition, and while vitamin D is derived from cholesterol (a steroid-like molecule), the proper broad category for steroids is lipid. Examples like cholesterol and steroid hormones (estrogen, testosterone, cortisol) illustrate their role and structure as lipids. Therefore, steroids are lipids.