Which of the lipids lack fatty acid?
**Core Concept**
Lipids are a diverse group of biomolecules that include fatty acids, triglycerides, phospholipids, and steroids. Fatty acids are hydrophobic chains of carbon and hydrogen atoms that are attached to a glycerol backbone in triglycerides and phospholipids. However, not all lipids contain fatty acids.
**Why the Correct Answer is Right**
The correct answer is a type of lipid that does not contain fatty acids. This is because it is a steroid, which is a type of lipid that is derived from a 17-carbon molecule called lanosterol. Steroids, such as cholesterol and cortisol, have a unique ring structure that is not composed of fatty acids. Instead, they are composed of a series of fused carbon rings that provide their hydrophobic and hydrophilic properties.
**Why Each Wrong Option is Incorrect**
* **Option A:** Triglycerides are a type of lipid that contains three fatty acid chains attached to a glycerol backbone. Therefore, this option is incorrect.
* **Option B:** Phospholipids are a type of lipid that contains one fatty acid chain attached to a glycerol backbone and a phosphate group. Therefore, this option is incorrect.
* **Option D:** Sphingolipids are a type of lipid that contains a fatty acid chain attached to a sphingosine backbone. Therefore, this option is incorrect.
**Clinical Pearl / High-Yield Fact**
Steroids, such as cortisol and aldosterone, play a crucial role in regulating electrolyte balance, blood pressure, and metabolism. They are also important in the development and maintenance of the reproductive system.
**Correct Answer: C. Steroids. Steroids.**