Which of the following structures is NOT a carbohydrate?

• A. Glucose (\(C_6H_{12}O_6\))
• B. Cellulose (a polymer of glucose)
• C. Sucrose (\(C_{12}H_{22}O_{11}\))
• D. Cholesterol (\(C_{27}H_{46}O\))

Answer: (D)

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) in a specific ratio, typically following the general formula (CH₂O)_n, where 'n' is a whole number.
2. Step 2: Analyze the molecular formula of glucose (\(C_6H_{12}O_6\)). It fits the general carbohydrate formula (CH₂O)_n, where n = 6, making it a carbohydrate.
3. Step 3: Examine cellulose, which is a polymer of glucose. Since it is made up of repeating glucose units, it is also classified as a carbohydrate.
4. Step 4: Look at sucrose (\(C_{12}H_{22}O_{11}\)). It is a disaccharide formed by the combination of glucose and fructose, and its molecular formula aligns with the carbohydrate definition.
5. Step 5: Evaluate cholesterol (\(C_{27}H_{46}O\)). Its molecular formula does not follow the (CH₂O)_n pattern, and it is classified as a lipid, not a carbohydrate. Therefore, cholesterol is the correct answer as it is NOT a carbohydrate.