Endoplasmic Reticulum Structure, Types and Functions | Class 11 & NEET Free Notes

Endoplasmic Reticulum Structure, Types and Functions

In this article we will discuss about:- Endoplasmic Reticulum Structure, Types and Functions

  • In 1897, observed by Garnier and named it as ergastoplasm
  • In 1945, first described by Porter, Claude and Fullman
  • In 1953, term given by porter
  • Present in all eukaryotes
  • All cells do not have Endoplasmic reticulum. It is generally absent in egg and embryonic cells

Endoplasmic Reticulum Structure

Components of endoplasmic reticulum


  • Formed by projection of nuclear membrane
  • They bear ribosomes on the surface
  • Contain ribophorin that bind the ribosomes


  • They are oval or rounded, vacuole like element
  • Many vesicles are free in the cytoplasm


  • They are tube like extensions
  • Tubules are irregular and branched
  • Free of ribosomes

Types of Endoplasmic Reticulum

I) Rough Endoplasmic Reticulum

  • Ribosomes binds with help of ribophorin protein
  • Mainly composed of cisternae
  • Abundantly occurs in cell which are engaged in protein synthesis and secretion
  • Mass of RER in cyton of nueron is called missals granules
  • g. Liver, pancreas and goblet cells

II) Smooth Endoplasmic Reticulum

  • Ribosomes and ribophorins are absent
  • Mainly composed of tubules
  • Occurs especially in those cells which are almost inactive in protein synthesis
  • It is well developed in cells that synthesis lipids
  • Mass of SER in retinal cell is called myeloid bodies

Functions of Endoplasmic Reticulum

  • It gives mechanical support so also called cytoskeleton of cell
  • Intracellular exchange: Transport of materials in cytoplasm from one place to another through the ER
  • Provides site for protein synthesis, because rough ER has ribosome’s
  • Lipids synthesized by smooth ER
  • Detoxification of drugs

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