Fluidity buffer present in cell membrane is
**Core Concept**
The fluidity buffer is a critical component of the cell membrane that helps regulate its fluidity, which is essential for maintaining membrane function and integrity. The fluidity buffer is composed of cholesterol and sphingolipids, which are embedded in the phospholipid bilayer.
**Why the Correct Answer is Right**
The fluidity buffer works by inserting itself into the phospholipid bilayer and altering its packing density. Cholesterol, a key component of the fluidity buffer, has a hydrophobic tail that interacts with the fatty acid chains of phospholipids, while its hydrophilic head interacts with water. This interaction helps to stabilize the membrane and prevent it from becoming too fluid or too rigid. The fluidity buffer also helps to regulate the movement of molecules across the membrane by altering its fluidity.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not specify a component of the fluidity buffer. While phospholipids are a crucial component of the cell membrane, they are not the fluidity buffer itself.
**Option B:** This option is incorrect because it refers to a different aspect of membrane function. The fluidity buffer is not responsible for maintaining membrane potential.
**Option C:** This option is incorrect because it refers to a different type of molecule. The fluidity buffer is composed of cholesterol and sphingolipids, not proteins.
**Clinical Pearl / High-Yield Fact**
The fluidity buffer is essential for maintaining membrane function and integrity. Disruptions to the fluidity buffer, such as those caused by cholesterol deficiency, can lead to changes in membrane fluidity and function.
**Correct Answer:** C. Cholesterol