Which of the following correctly describes the structural organization of the cell membrane?

• A. A rigid cellulose wall with scattered lipids
• B. A single layer of phospholipids with proteins on the outside only
• C. A double layer of proteins with phospholipids on the surface
• D. A phospholipid bilayer with embedded proteins

Answer: (D)

Verified step by step guidance

1. Understand the structure of the cell membrane: The cell membrane, also known as the plasma membrane, is primarily composed of a phospholipid bilayer. This bilayer is made up of two layers of phospholipids, with their hydrophilic (water-attracting) heads facing outward and their hydrophobic (water-repelling) tails facing inward.
2. Recognize the role of proteins in the membrane: Proteins are embedded within the phospholipid bilayer. These proteins can either span the entire bilayer (integral proteins) or be attached to the surface (peripheral proteins). They play roles in transport, signaling, and structural support.
3. Eliminate incorrect options: A rigid cellulose wall with scattered lipids is incorrect because cellulose is found in plant cell walls, not in the cell membrane. A single layer of phospholipids with proteins on the outside only is incorrect because the membrane is a bilayer, not a single layer. A double layer of proteins with phospholipids on the surface is incorrect because the bilayer is made of phospholipids, not proteins.
4. Confirm the correct description: The correct description of the cell membrane is 'A phospholipid bilayer with embedded proteins,' as it accurately reflects the structural organization of the membrane.
5. Relate the structure to function: The phospholipid bilayer provides a semi-permeable barrier, while the embedded proteins facilitate transport, communication, and other essential cellular functions.