Final answer:
The correct matching of molecules to the functions they provide in the phospholipid bilayer of cell membranes is: proteins for transport, carbohydrates for cell recognition, cholesterol for flexibility, and phospholipids for structure.
Step-by-step explanation:
The phospholipid bilayer of cell membranes is an essential component that defines the boundaries and functionalities of cells. Molecules mixed into the bilayer serve specific functions, maintaining the integrity and regulation of the cell membrane. It is important to match each molecule with its correct role in the cell membrane. Here is the correct matching:
- Proteins: Form transporters that allow selective passage of ions and molecules through the membrane.
- Carbohydrates: Part of the cell's recognition sites, often attached to proteins on the outward-facing surface of the membrane to help cells identify each other.
- Cholesterol: Provide flexibility to the membrane, this flexibility allows the membrane to maintain its integrity under various temperatures and conditions.
- Phospholipids: Form the bilayer and provide the basic structure of the membrane.
Integral proteins span the membrane and act as channels or transporters, while peripheral proteins associated with the outside of the membrane can be involved in cell recognition (often with attached carbohydrates) or signal transduction. Cholesterol molecules are interspersed within the bilayer, contributing to membrane fluidity and stability. Together, these components function in a dynamic and coordinated fashion, dubbed the fluid mosaic model.