Question

What is the primary composition of lipid rafts found in plasma membranes?

• A. Phospholipids and carbohydrates
• B. Cholesterol and sphingolipids
• C. Proteins and nucleic acids
• D. Glycoproteins and triglycerides

Hint:

{Lipid Rafts = Cholesterol + Sphingolipids}. These domains act as {signaling platforms} in the plasma membrane.

Answer 1

The Correct Option is B

Concept: Lipid rafts are specialized microdomains in the plasma membrane that are more ordered and tightly packed than the surrounding membrane. They serve as platforms for cell signaling, membrane trafficking, and protein sorting.
Step 1:Structure of the plasma membrane.
The plasma membrane mainly consists of phospholipids, proteins, and cholesterol arranged in a fluid mosaic structure. However, some regions form distinct microdomains called lipid rafts.
Step 2:Composition of lipid rafts.
Lipid rafts are enriched in: [ \text{Cholesterol} \quad \text{and} \quad \text{Sphingolipids} ] These molecules pack tightly together, creating a more ordered and less fluid region of the membrane.
Step 3:Functional importance.
These domains help organize membrane proteins involved in signaling pathways and play roles in processes such as endocytosis and immune responses. Thus, the primary composition of lipid rafts is cholesterol and sphingolipids.