Introduction of Endoplasmic Reticulum | Structure | Functions | Types

Introduction of Endoplasmic reticulum: Endoplasmic reticulum consists of flattened single membrane vesicles. These have the same lipid bilayer structure but thinner than the cell membrane (about 7mm). The endoplasmic reticulum is of two types; rough (RER) and smooth (SER). Only the rough of endoplasmic reticulum type has small granules known as ribosomes.

Introduction of Endoplasmic Reticulum | Structure | Functions | Types

Types Introduction of Endoplasmic Reticulum: 

There are two types Introduction of Endoplasmic Reticulum

  1. Rough endoplasmic reticulum
  2. Smooth endoplasmic reticulum

Introduction of Endoplasmic Reticulum | Structure | Functions | Types

1. Rough Endoplasmic Reticulum

Small granules like structure attached to the surface of endoplasmic reticulum due to this quality they are called Rough endoplasmic reticulum. These ribosomes are responsible for the synthesis of proteins. These synthesized proteins are either stored in the cytoplasm or extra proteins are transported to another part of the cell.

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2. Smooth Endoplasmic Reticulum

Smooth endoplasmic reticulum lacks ribosomal granules. They play a vital role in the metabolism. They also provide mechanical support to the cell.

Introduction of Endoplasmic Reticulum | Structure | Functions | Types

Functions of Endoplasmic reticulum

  1. Functions rough endoplasmic reticulum RER is concerned with protein synthesis while SER is concerned with lipids and glycoprotein synthesis.
  2. The cisternae (enclosed spaces) of the endoplasmic reticulum play a role in the exchange of material between the cell and the extracellular fluid.
  3. The exchange of material takes place through the process of pinocytosis done by endoplasmic reticulum.
  4. Forms the skeletal framework.
  5. Allow active transport of cellular materials.
  6. Metabolic activities due to the presence of different enzymes.
  7. Provides an increased surface area for cellular reactions.
  8. Formation of nuclear membrane during cell divisionIntroduction of Endoplasmic Reticulum | Structure | Functions | Types

The Function of Smooth ER.

  1. Help in the metabolism of different molecules.
  2. Help in Lipid synthesis.
  3. Allow Glycogen synthesis within the cell.
  4. Help in Steroid synthesis like cholesterol, progesterone, testosterone, etc.

The Function of Rough ER

  1. It provides the site for protein synthesis.
  2. It helps in the transport of proteins.


  1. The Mammalian Endoplasmic Reticulum-Associated Degradation System
    Olzmann, J. A.Kopito, R. R.Christianson, J. C.
  2. Endoplasmic Reticulum Targeting and Insertion of Tail-Anchored Membrane Proteins by the GET Pathway
    Denic, V.Dotsch, V.Sinning, I.