The cell membrane is a thin, flexible layer that surrounds the cells of all living organisms. It separates the inside of the cell from the outside environment and regulates the movement of substances in and out of the cell.
The cell membrane is primarily composed of two types of molecules: lipids and proteins. The most common type of lipid in the cell membrane is phospholipids. They have a hydrophilic (water-loving) head and a hydrophobic (water-hating) tail. The phospholipids are arranged in a bilayer with the hydrophilic heads facing outward and the hydrophobic tails facing inward.
The proteins in the cell membrane have a variety of functions, such as transporting molecules across the membrane, serving as receptors for chemical signals, and anchoring the membrane to the cell's cytoskeleton.
Carbohydrates are also present in the cell membrane, but they are attached to the surface of the lipids and proteins, forming glycolipids and glycoproteins. They play a role in cell-to-cell recognition and communication.
Therefore, the correct option is (C) lipids and proteins, as they are the main components of the cell membrane, while carbohydrates are also present but in a minor proportion.