Which of the following is an example of a carbohydrate?

• A. Glucose
• B. Hemoglobin
• C. Triglyceride
• D. Adenine

Answer: (A)

Verified step by step guidance

1. Step 1: Begin by understanding 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 a primary energy source for living organisms and include sugars, starches, and fibers.
2. Step 2: Examine the options provided. Glucose is a simple sugar (monosaccharide) and fits the definition of a carbohydrate. Hemoglobin is a protein responsible for oxygen transport in blood, triglycerides are lipids (fats), and adenine is a nitrogenous base found in nucleic acids.
3. Step 3: Recall the structural formula of glucose, which is C₆H₁₂O₆. This formula adheres to the carbohydrate ratio of carbon, hydrogen, and oxygen atoms (1:2:1). This confirms glucose as a carbohydrate.
4. Step 4: Eliminate the other options systematically. Hemoglobin is composed of amino acids, not sugars. Triglycerides consist of glycerol and fatty acids, and adenine is part of DNA and RNA, not a carbohydrate.
5. Step 5: Conclude that glucose is the correct answer because it is a carbohydrate, while the other options belong to different macromolecule categories (proteins, lipids, and nucleic acids).