What describes the structure of the cell surface membrane?

The structure of the cell surface membrane is best described by the fluid mosaic model. This model illustrates that the membrane is not a rigid structure; instead, it is a dynamic and flexible arrangement of various components. The "fluid" aspect refers to the movement of phospholipids and proteins within the layer, allowing the membrane to be flexible and self-healing. The "mosaic" aspect refers to the diverse array of proteins that are embedded within or attached to the phospholipid bilayer, creating a patchwork effect.

This model accounts for various functions of the membrane, including the permeability of certain molecules, the movement of substances in and out of the cell, and communication with other cells through receptor proteins. The fluid mosaic model effectively captures the complexity and functionality of the cell membrane, making it the most accurate representation of its structure.

Other models like the layered model with stacked phospholipids or solid state model do not accurately reflect the fluidity and dynamic nature of the membrane. The unit membrane model, while historically relevant, does not incorporate the complexity and variations found in actual cell membranes.