Final answer:
The key components of cell membranes are phospholipids arranged in a bilayer, with embedded proteins and cholesterol, allowing selective passage of substances and contributing to membrane fluidity.
Step-by-step explanation:
Key Components of Cell Membranes
The primary molecules that make up cell membranes and are arranged in bilayers to form these membranes are known as phospholipids. These phospholipid bilayers function as barriers to the passage of molecules and ions, enabling the cell to maintain a distinct internal environment. Within the cell membrane, protein molecules are embedded, forming channels that allow for the selective passage of specific ions and molecules. These proteins can be integral or peripheral, with some having attached carbohydrates and contributing to various functions. Additionally, cholesterol is found within the cell membrane, adding to the fluidity and flexibility of the structure.
The arrangement in the phospholipid bilayer consists of two layers of phospholipids with hydrophobic tails pointing inward and hydrophilic heads facing the aqueous exterior and interior of the cell. This configuration provides a semi-permeable membrane that can regulate the flow of substances in and out of the cell. The glycerophospholipid bilayer, along with other components like cholesterol and proteins, adjusts the membrane's properties and controls particle movement as needed, maintaining the stability and integrity of the cell.