Which of the following is a primary function of lipids in biological systems?

• A. Encoding genetic information
• B. Energy storage
• C. Catalyzing biochemical reactions
• D. Transporting oxygen in the blood

Answer: (B)

Verified step by step guidance

1. Understand the primary functions of lipids in biological systems. Lipids are a diverse group of biomolecules that include fats, oils, phospholipids, and steroids. Their roles differ significantly from those of proteins and nucleic acids.
2. Review the role of lipids in energy storage. Lipids, particularly triglycerides, are highly efficient molecules for storing energy due to their high caloric content (9 kcal per gram compared to 4 kcal per gram for carbohydrates and proteins). This makes them a primary energy reservoir in organisms.
3. Compare the functions of lipids with the other options provided. Lipids do not encode genetic information; this is the role of nucleic acids (DNA and RNA). Lipids also do not catalyze biochemical reactions; enzymes, which are proteins, perform this function. Transporting oxygen in the blood is primarily the role of hemoglobin, a protein found in red blood cells.
4. Recognize that the correct answer is 'Energy storage' because this is a well-established primary function of lipids in biological systems. Lipids are stored in adipose tissue and mobilized when energy is needed.
5. Conclude that understanding the distinct roles of biomolecules (lipids, proteins, nucleic acids, carbohydrates) is essential for solving such problems. Lipids are specialized for energy storage, membrane structure, and signaling, but not for genetic encoding or catalysis.