Structure of Cell Membrane

The diagram of cell membrane shows its structure clearly. Following components make up a cell membrane:

Phospholipid

• A phospholipid molecules is an amphipathic molecule made up of a hydrophilic polar phosphate “head,” and a hydrophobic non-polar lipid “tail”.
• Cell membrane comprises two layers of phospholipids arranged in a bilayer.
• The interior has hydrophobic lipid tails facing each other.
• Fluid inside and outside the cell contacts outward-facing polar phospholipid heads.

Membrane Proteins

There are two types of proteins that are usually associated with the cell membrane:

Integral Proteins

These are found embedded in the membrane. It is further of three types:

• A channel protein: It is a type of an integral protein which selectively allows particular molecules like ions to pass into or out of the cell.
• Recognition proteins: It functions to identify a cell so that other cells can identify it.
• Glycoprotein: It is a protein that has carbohydrate molecules attached to it, which further extend into the extracellular matrix. The linked carbohydrate tags on glycoproteins facilitates in cell recognition.

Peripheral Proteins

• Found on inner or outer lipid bilayer surface, or attached to integral proteins.
• Serve specific cell functions; e.g., intestinal peripheral proteins act as digestive enzymes.
• Help in nutrient absorption by breaking down molecules for bloodstream passage.

Carbohydrates

• Carbohydrates are found externally, often attached to lipids or proteins forming glycolipids and glycoproteins.
• In eukaryotes, it is crucial for cell recognition and facilitates interactions and information exchange.
• Viral infections often result from viruses binding to cell receptors via carbohydrates.
• Glycoproteins play significant roles in cell adhesion and communication between cells.

Cholesterol

• Cholesterol is found between phospholipids in the cell membrane.
• Provides stability and structure to the membrane.
• Interacts with hydrophobic tails, making them rigid and less permeable.
• Controls membrane fluidity, acting as a buffer against temperature changes.
• Expands range of temperatures for membrane fluidity maintenance.

The diagram of cell membrane shows that the cell membrane consists of a semipermeable lipid bilayer. The function of cell membrane is to regulate the transport of materials entering and exiting the cell. The diagram of cell membrane in cross-section shows that the main components are phospholipids, cholesterol, integral proteins, peripheral proteins and carbohydrates. The diagram of cell membrane class 9 is important for biology examinations and should be studied carefully.

The cell membrane diagram is given below: