Endoplasmic Reticulum and Mitochondria


Tejinder Kaur, Academic Content Creator at Edumarz

Endoplasmic Reticulum:

  • It is a complex tubular network of membrane bound tubes and sheets which are found exclusively in the eukaryotic cell cytoplasm. Exception : Sperm cell and RBC

  • It is of two types:

  1. Rough Endoplasmic Reticulum (RER)

  2. Smooth Endoplasmic Reticulum (SER)

Rough Endoplasmic Reticulum (RER) –

  • The ER has several ribosomes embedded on its outer surface.

  • It is named so because of its appearance.

  • Ribosomes are responsible for the synthesis of protein.

  • RER is prominently observed in cells where protein synthesis happens such as in Liver cells.


  • It is responsible for the synthesis of proteins.

  • It also plays a role in the folding of proteins and its sorting.

Smooth Endoplasmic Reticulum (SER) –

  • The ER which does not have ribosomes on its surface.

  • It is named so because of its smooth appearance.

  • This SER helps in the production of lipids.

  • SER is also responsible for transporting the products of RER to other cell organelles such as the Golgi Apparatus.


  • It helps in the synthesis of essential lipids such as Cholesterol.

  • It is responsible for the synthesis of hormones.

  • It is the storehouse of Calcium ions which play a role in the nervous and muscular system.


  • Mitochondria is known as the “powerhouse of the cell”.

  • It is a double membrane bound cell organelle present in eukaryotic cell cytoplasm that produces the ATP, energy currency of the cell.

  • Since it is able to make its own DNA and ribosomes, it is called a Semi Autonomous Organelle.


  • It is a double membrane organelle found in both plant and animal cells.

  • The structure consists of the outer membrane, inner membrane and a gel-like matrix.

  • Both the outer and inner membrane are separated by Inter membrane space.

  • The outer membrane has special proteins on its surface called porins.

  • The inner membrane is folded to form cristae.

  • The matrix of mitochondria is gel like and consists of enzymes, proteins, ribosomes and organic molecules.


  • It helps in regulating the metabolic activities of the cell.

  • It promotes cell growth.

  • It plays an important role in programmed cell death, also known as apoptosis.

  • It is also involved in cellular respiration.

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