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Endoplasmic reticulum

Endoplasmic reticulum
Introduction
Endoplasmic reticulum is a network, which is continuous with plasma membrane at one end and also appears to be in contact with the nuclear envelope.
Structure
  • Endoplasmic reticulum is visible with electron microscope as a network of channels extending throughout the cytoplasm.
  • They vary widely in appearance from cell to cell.
  • These channels are filled with material, which is separated from the cytoplasmic material by the spherical or tubular membranes, called cisternae.
Functions
  1. It provides mechanical support to the various cellular organelles in cytoplasm.
  2. It plays an important role in transport of materials from one part of the cell to the other.
Forms
There are two morphological forms of endoplasmic reticulum i.e,
  1. Rough form with attached ribosomes
  2. Smooth form without ribosomes
Rough Endoplasmic Reticulum (RER)
On this form, ribosomes are attached, so it is called as rough endoplasmic reticulum.
Function
It is involved in the synthesis of proteins. After synthesis, the proteins are either stored in the cytoplasm or exported out of the cell through these channels.
Smooth Endoplasmic Reticulum (SER)
This form of endoplasmic reticulum is without ribosomes, so called as smooth endoplasmic reticulum.
Functions
  1. It helps in metabolism of a number of different types of molecules particularly lipids.
  2. It also helps to detoxify the harmful drugs.
  3. In some cells, it is responsible for transmission of impulses e.g, muscle cells, and nerve cells.
  4. It also plays an important role in transport of materials from one part of the cell to the other.

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