Endoplasmic Reticulum (ER)

• The endoplasmic reticulum is a network of tubes and sheets .
• It looks like long tubules or round or oblong bags .
• This organelle makes and transports proteins in the cell.
• There are two kinds of Endoplasmic Reticulum:

• Rough endoplasmic reticulum(RER) : It has tiny particles called ribosomes attached to its surface thus making it look rough. 
• It is responsible for production of proteins .

• Smooth endoplasmic reticulum(SER) : Does not have any ribosomes attached hence looks smooth.
  • It is responsible for production of fats and steroids .

What are Ribosomes?

Ribosomes are sites for production of protein . 

• So all our protein requirements are taken care of by the ribosomes and thus by the rough endoplasmic reticulum. 
• Some of the proteins and lipids are used to build and maintain the cell membrane, in a process called membrane biogenesis .
• Other proteins and lipids function as enzymes and hormones .

• The Endoplasmic reticulum is responsible for storing and transporting these fats and proteins throughout the cell.