These slides are related to endoplasmic reticulum. Its introduction , structure and functions.

1. ENDOPLASMIC
RETICULUM
Submitted to: Sir Ali Umar
Submitted by: Ali Rizwan
Roll No : F20-BS-ZOOL-1033
Semester: 5th

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.

4. Definition :
The endoplasmic reticulum (ER) is a network
of membrane-enclosed tubules and sacs
(cisternae) that extends from the nuclear
membrane throughout the cytoplasm .
The entire endoplasmic reticulum is enclosed
by a continuous membrane and is the largest
organelle of most eukaryotic cells.

6. 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.

8. 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.

10. 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.

11. 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.

12. FUNCTION
🠶 Cell Skeleton Formation.
🠶 Rough ER form protein.
🠶 Smooth ER form Lipid and Steroid.
🠶 Segregation of protein.

13. 🠶 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.

14. References :
https://www.ncbi.nlm.nih.gov/books/NBK9889/
https://www.slideshare.net/HarinathaReddyA/cell-organelles-
endoplasmic-reticulum
https://images.app.goo.gl/k1i2X5FmSybK6RhPA
https://images.app.goo.gl/JHDuuodNmz73YAmu9

15. THANK YOU