Which type of lipid do plants primarily use for long-term energy storage?

• A. Waxes
• B. Triglycerides (oils)
• C. Steroids
• D. Phospholipids

Answer: (B)

Verified step by step guidance

1. Understand the role of lipids in energy storage: Lipids are a diverse group of molecules that include triglycerides, phospholipids, steroids, and waxes. Among these, triglycerides are the primary molecules used for long-term energy storage in both plants and animals.
2. Recognize the difference between plant and animal triglycerides: Plants primarily store energy in the form of oils, which are liquid triglycerides at room temperature due to their unsaturated fatty acid chains. Animals, on the other hand, often store energy in the form of solid fats, which have saturated fatty acid chains.
3. Eliminate incorrect options: Waxes are used for protective coatings, steroids are signaling molecules, and phospholipids are structural components of cell membranes. None of these are primarily used for long-term energy storage.
4. Focus on triglycerides: Triglycerides consist of three fatty acid chains attached to a glycerol backbone. In plants, these are often unsaturated, making them oils. This structure allows plants to efficiently store energy for long periods.
5. Conclude that triglycerides (oils) are the correct answer: Plants rely on oils as their primary form of long-term energy storage due to their high energy density and liquid state, which facilitates storage and usage.