Structure of Cell Membrane

Structure Of Cell Membrane: The cell is enclosed by a single membrane called cell membrane. Cell membrane separates internal cells environment from its surroundings. The cell membrane is also known as Plasma membrane or plasmalemma. The cell membrane is a thin wall comprises of an unyielding framework of polysaccharide chains that are crosslinked with the help of short peptide chains. The cell membrane outer surface is coated with lipopolysaccharide.

Structure of Cell Membrane

The Structure of Cell Membrane

Structure Of Cell Membrane is very complex.The cell membrane comprises about 45% lipid and 55% protein. The cell membrane or plasma membrane has a typical width of 75A°. In the cell membrane, the principal lipids are phospholipids, sphingolipids, and cholesterol. An imperative feature of these lipids is they are the collection of hydrophobic (water-insoluble) hydrocarbon sections and hydrophilic (water soluble) units. Cell membrane comprises charged units (e.g. Phosphate or amino groups) and uncharged units (e.g. Hexose). In water, such compounds positioned themselves in such a technique that only the hydrophilic section is exposed to water.

The hydrophobic components of cell membrane discrete molecules tend to contact with other. Due to these hydrophobic components of cell membrane accomplished by the formation of bilayers.

Proteins Present in structure Of Cell Membrane:

There are two types of proteins found in cell membrane:

  1. Intrinsic or integral proteins
  2. Extrinsic or peripheral proteins

Structure of Cell Membrane

  • Intrinsic or integral proteins

Integral proteins are incompletely or totally immersed in the lipid bilayer and problematic to remove.

  • Extrinsic or peripheral proteins.

Peripheral proteins are bound to the surface of the membrane. Peripheral proteins intermingle only with the hydrophilic groups. Peripheral proteins are voluntarily removed by extraction with an aqueous medium.

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Fluid Mosaic Model.

The model of the arrangement of lipids and proteins in the membrane is known as the fluid mosaic model.

Structure of Cell Membrane is well explained by the fluid mosaic model.The fluid mosaic model was foremost proposed by S.J. Singer and Garth L. Nicolson in 1972 to enlighten the structure of the cell membrane. The fluid mosaic model designates the structure of the cell membrane. According to the fluid mosaic model cell membrane act as a mosaic of components and it includes following components:

  1. Phospholipids
  2. Cholesterol
  3. Protein
  4. Carbohydrates

Structure of Cell Membrane

Due to the presence of these components cell membrane has a fluid character. Plasma membranes range from 5 to 10 nm in width. The amounts of proteins, lipids, and carbohydrates in the plasma membrane fluctuate with cell type. For example, myelin comprises 18% protein and 76% lipid. The mitochondrial inner membrane comprises 76% protein and 24% lipid.

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