Which one of the following terms best describes the structure of the cell membrane?
A. Fluid mosaic model
B. Static mosaic model
C. Quaternary structure
D. Multilayered structure
The Correct Answer and Explanation is :
Correct Answer: A. Fluid Mosaic Model
The fluid mosaic model best describes the structure of the cell membrane. This model was proposed by Singer and Nicolson in 1972 and remains the widely accepted explanation of how cell membranes function.
Explanation
The cell membrane, also known as the plasma membrane, is a semi-permeable structure that separates the internal environment of the cell from its external surroundings. The fluid mosaic model describes the cell membrane as a dynamic and flexible bilayer of phospholipids embedded with proteins, carbohydrates, and cholesterol molecules.
Key Features of the Fluid Mosaic Model
- Phospholipid Bilayer
- The cell membrane is made up of a bilayer of phospholipids, where the hydrophilic (water-loving) heads face outward and the hydrophobic (water-fearing) tails face inward. This arrangement helps maintain the membrane’s stability and selectively allows molecules to pass through.
- Fluid Nature
- The phospholipids and proteins within the membrane are not rigid; they move laterally, making the membrane flexible and self-healing. This fluidity is essential for cell processes such as cell signaling, transport, and endocytosis.
- Mosaic Arrangement
- The membrane is called a mosaic because of the diverse molecules embedded within it. These include:
- Proteins (integral and peripheral) that serve as channels, carriers, and receptors.
- Cholesterol that maintains fluidity and prevents the membrane from becoming too rigid or too fluid.
- Carbohydrates attached to proteins (glycoproteins) and lipids (glycolipids), which play a role in cell recognition and signaling.
Why Not the Other Options?
- B. Static Mosaic Model – Incorrect because the membrane is not static; it is fluid and constantly moving.
- C. Quaternary Structure – Incorrect because this term refers to protein structure, not the membrane.
- D. Multilayered Structure – Incorrect because the membrane is a bilayer, not multiple layers.
The fluid mosaic model accurately represents how the membrane is dynamic, selectively permeable, and essential for life functions.
Now, I’ll generate an image of the fluid mosaic model of the cell membrane.
Here is the generated illustration of the Fluid Mosaic Model of the Cell Membrane. It visually represents the phospholipid bilayer, embedded proteins, cholesterol molecules, and glycoproteins with clear labeling. Let me know if you need any modifications or further explanations!