Final answer:
The plasma membrane is described by the fluid mosaic model due to its composition of a fluid lipid bilayer with various components like proteins and carbohydrates that can move laterally, maintaining a dynamic but intact barrier around the cell.
Step-by-step explanation:
The fluid mosaic model describes the plasma membrane as a dynamic structure characterized by a mix of various components, including phospholipids, proteins, cholesterol, and carbohydrates, that all contribute to the membrane's fluid nature. Among the available options, the correct answer is that it is composed of a fluid lipid bilayer with embedded proteins. Phospholipids form a bilayer where the hydrophobic tails face inward and the hydrophilic heads face the extracellular fluid or the cell's cytoplasm.
Proteins, some spanning the membrane, add to the mosaic pattern while enabling transport and communication. Carbohydrates often attach to these proteins or lipids, contributing to cell recognition. The fluid character allows for lateral movement within the membrane, crucial for function and maintaining the integrity of the cell. This dynamic and configurable nature is essential for various cellular processes including attaching to other cells and facilitating the transport of molecules. The plasma membrane's structure is therefore not rigid but maintains a semi-permeable barrier despite its fluidity.