Which of the following statements is NOT a function of lipids in the human body?

• A. Lipids provide insulation and protection for organs.
• B. Lipids serve as a major energy storage molecule.
• C. Lipids act as catalysts to speed up biochemical reactions.
• D. Lipids are essential components of cell membranes.

Answer: (C)

Verified step by step guidance

1. Step 1: Understand the role of lipids in the human body. Lipids are a diverse group of molecules that include fats, oils, phospholipids, and steroids. They play several critical roles, such as energy storage, insulation, protection, and forming cell membranes.
2. Step 2: Analyze the first statement: 'Lipids provide insulation and protection for organs.' This is correct because lipids, particularly adipose tissue, help insulate the body and cushion organs from physical damage.
3. Step 3: Analyze the second statement: 'Lipids serve as a major energy storage molecule.' This is correct because lipids, especially triglycerides, are stored in adipose tissue and serve as a long-term energy reserve.
4. Step 4: Analyze the third statement: 'Lipids act as catalysts to speed up biochemical reactions.' This is incorrect because lipids do not function as catalysts. Catalysts in biochemical reactions are typically enzymes, which are proteins, not lipids.
5. Step 5: Analyze the fourth statement: 'Lipids are essential components of cell membranes.' This is correct because phospholipids are a major component of the lipid bilayer in cell membranes, providing structure and regulating the movement of substances in and out of cells.