The cell membrane is primarily composed of which structure?

The cell membrane is primarily composed of which structure?

• A. Phospholipid bilayer
• B. Carbohydrate chain
• C. Protein channel
• D. DNA

Answer: (A)

The cell membrane’s basic scaffold is a phospholipid bilayer. Phospholipids have a water-loving head and a water-fearing tail, so in the watery environment of the cell they arrange into two layers with heads facing outward and tails tucked inward. This creates a flexible, semi‑permeable barrier that defines the cell and controls what can pass through. Other components sit within or on this bilayer and support its functions, but they don’t form its main structure. Carbohydrate chains are typically attached to proteins or lipids on the outer surface and help with cell recognition, not the overall membrane framework. Protein channels are embedded in the membrane to assist transport, while DNA resides in the nucleus or organelles, not in the membrane itself. So the phospholipid bilayer is the primary structure of the cell membrane.

The cell membrane’s basic scaffold is a phospholipid bilayer. Phospholipids have a water-loving head and a water-fearing tail, so in the watery environment of the cell they arrange into two layers with heads facing outward and tails tucked inward. This creates a flexible, semi‑permeable barrier that defines the cell and controls what can pass through.

Other components sit within or on this bilayer and support its functions, but they don’t form its main structure. Carbohydrate chains are typically attached to proteins or lipids on the outer surface and help with cell recognition, not the overall membrane framework. Protein channels are embedded in the membrane to assist transport, while DNA resides in the nucleus or organelles, not in the membrane itself. So the phospholipid bilayer is the primary structure of the cell membrane.