The document describes the endoplasmic reticulum (ER), which is a network of membranous tubules and sacs found in eukaryotic cells. There are two types: smooth ER, which forms lipids and steroids, and rough ER, which has ribosomes attached and is involved in protein synthesis. The ER has a double membrane structure with cisternae, tubules, and vesicles. It performs important cellular functions like protein transport, detoxification, and ATP synthesis.

1. ENDOPLASMIC RETICULUM
BY- SHEETAL BISHT

2. CONTENTS
 INTRODUCTION
 TYPES OF ENDOPLASMIC RETICULUM
 STRUCTURE
 FUNCTION

3. INTRODUCTION
 HISTORY : First observed by light microscope and it was called
ergastoplasm.
 Discovered by porter.
 It’s found in all Eukaryotic cell except Erythrocytes (RBC) of mammals.
 In prokaryotic cells it is absent.
 In muscle cells it is known as sarcoplasmic reticulum.
 Found undifferentiated and small in eggs and embryonic cell.

5. TYPES OF ENDOPLASMIC RETICULUM
1. Agranular / Smooth Endoplasmic Reticulum (SER) :- In these SER
ribosomes are absent on the surface.
• It forms Lipid.
• These are spheroidal 50 – 500 nm in size.
• These are more abundant in glycogen storing liver cells, intestinal
cells, adipose cell, leucocytes and retinal cells.

7. 2. Granular Reticulum / Rough Endoplasmic Reticulum
(RER) :-
Ribosomes are attached by riboprotein to RER.
• It’s found mostly that secrets material continuously.
• Protein synthesis occurs in presence of Ribosome.
• RER is the ergastoplasm or basophilic bodies or Nissel
bodies.
• This is involved in metabolism and transport of protein.

9. STRUCTURE
• It’s double membranous organ.
• Endomembranes have 2 faces.
a) Cytoplasmic or Protoplasmic Face – Ribosome present.
b) Luminal Face.
• Following types of structure are found in it-
1. Cisternae : It’s elongated, flattened, and unbranched.
These are about 40-50 µ thick.

10. 2. Tubules : Elongated, smooth walled/branched.
• Diameter – about 50-190 µ.
• Found in non-secretory cells like – muscle cells, develop in
spermatid of guinea pig.
3. Vesicles : They are rounded, spherical.
• It’s found in which cells they are busy in protein synthesis
and in liver and pancreatic cells.
• It forms organelles like spheriosome, peroxysome.

11. FUNCTION
 Cell Skeleton Formation.
 Rough ER form protein.
 Smooth ER form Lipid and Steroid.
 Segregation of protein.

12.  Formation of Plasmodesmeta.
 Detoxification occurs by ER.
Eg – In liver cell, detoxification of prussic acid occurs.
 ATP synthesis : - ER membranes are the sites of ATP
synthesis.
 Between cell membrane and nucleus genetic material
transportation occurs by ER.

13. THANK YOU