Which of the following is NOT an example of a carbohydrate?

• A. Cellulose
• B. Cholesterol
• C. Glucose
• D. Sucrose

Answer: (B)

Verified step by step guidance

1. Step 1: Understand the definition of carbohydrates. Carbohydrates are organic molecules composed of carbon (C), hydrogen (H), and oxygen (O) atoms, typically in a ratio of 1:2:1. They serve as energy sources and structural components in living organisms.
2. Step 2: Review the examples provided in the question. Cellulose, glucose, and sucrose are all carbohydrates. Cholesterol, however, is a lipid, not a carbohydrate. Lipids are hydrophobic molecules primarily composed of carbon and hydrogen, and they include fats, oils, and steroids.
3. Step 3: Analyze the molecular structure of each option. For example, glucose (C₆H₁₂O₆) is a monosaccharide, sucrose (C₁₂H₂₂O₁₁) is a disaccharide, and cellulose is a polysaccharide made of glucose units. Cholesterol, on the other hand, has a steroid structure with a hydroxyl group (-OH) and is not composed of carbohydrate monomers.
4. Step 4: Recall the biological roles of these molecules. Carbohydrates like glucose and sucrose are involved in energy metabolism, while cellulose provides structural support in plant cell walls. Cholesterol is involved in membrane fluidity and serves as a precursor for steroid hormones.
5. Step 5: Conclude that cholesterol is the correct answer because it does not fit the definition or structural characteristics of carbohydrates, unlike the other options provided.