Cell Membrane | Introduction, Structure & Function

By | July 20, 2019

Cell Membrane Definition and Function :

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

Cell membrane Structure

The Structure of the Cell Membrane is described below:

An imperative feature of these lipids is they are the collection of hydrophobic (water-insoluble) hydrocarbon sections and hydrophilic (water-soluble) units. It 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 are discrete molecules tend to contact with others. Due to these hydrophobic components are accomplished by the formation of bilayers.

What is the Cell Membrane made of:

It comprises about 45% lipid and 55% protein. Plasma Membrane has a typical width of 75Aį. In it, the principal lipids are phospholipids, sphingolipids, and cholesterol.

Cell Membrane Location

It is basically located on the outer side of a cell. It is a border which separates the cell from other cells inner substances.

Cell Membrane Diagram

Cell Membrane

Proteins Present in structure Of Cell Membrane:

There are two types of proteins found in it :

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

Structure of Cell Membrane

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

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.

† † † † † † † † † † † † † † † † † † †You May Also Like:†Prokaryotic Vs Eukaryotic Cell

Plasma Membrane Diagram

Cell Membrane

Fluid Mosaic Model.

Cell Membrane Characteristics are described below:

The model of the arrangement of lipids and proteins in the membrane is known as the fluid mosaic model. It’s 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. The fluid mosaic model designates the structure. According to the fluid mosaic model, it acts as a mosaic of components and it includes the following components:

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

Structure of Cell Membrane

Due to the presence of these components, It 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.

Importance Of Cell Membrane††

Functions of the cell membrane are very diverse due to its complex structure.† It, 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. It 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.

You May Also Like:†Prokaryotic Vs Eukaryotic Cell Ė Difference and Comparison

 

Functions of the Cell Membrane

Cell Membrane Function

Lipid Bilayer Function: Main Functions of the Cell Membrane are described below:

  1. It clasps the cell in the organized form.
  2. It is a selectively penetrable or permeable membrane which permits water, certain compulsory nutrients, and metal ions to permit freely among it.
  3. It stashes waste products
  4. It keeps out toxic materials from the cell.
  5. It comprises receptors to bind monitoring substances
  6. It binds to hormones which regulate the countless metabolic activities.
  7. It assists as a sordid of attachment for the cytoskeleton in some organisms.
  8. Cell supports the cell and supports in maintaining the shape of the cell.
  9. It is the collection of lipids and proteins.
  10. It Lipids provide flexibility to cell membranes and proteins preserve the chemical microclimate of the cell and also aid in the transmission of molecules across the membrane.

Cell Membrane Analogy

Cell Membrane

Plasma Membrane Vs Cell Membrane

Cell Membrane

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