Which class of macromolecules consists primarily of carbon, hydrogen, and oxygen in a ratio close to 1:2:1?

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

Answer: (D)

Verified step by step guidance

1. Understand the question: The problem asks which class of macromolecules consists primarily of carbon, hydrogen, and oxygen in a ratio close to 1:2:1. This ratio is a key characteristic of carbohydrates.
2. Review the composition of macromolecules: Proteins are composed of amino acids, which contain carbon, hydrogen, oxygen, nitrogen, and sometimes sulfur. Nucleic acids consist of nucleotides, which include carbon, hydrogen, oxygen, nitrogen, and phosphorus. Lipids are primarily composed of carbon, hydrogen, and oxygen, but their ratio is not close to 1:2:1.
3. Focus on carbohydrates: Carbohydrates are composed of carbon (C), hydrogen (H), and oxygen (O) atoms, typically in a ratio of 1:2:1. For example, glucose (C₆H₁₂O₆) follows this ratio.
4. Relate the ratio to the molecular formula: The general formula for carbohydrates is (CH₂O)ₙ, where 'n' represents the number of repeating units. This formula reflects the 1:2:1 ratio of carbon, hydrogen, and oxygen.
5. Conclude the reasoning: Based on the characteristic ratio and molecular composition, carbohydrates are the correct answer to the question.