Endoplasmic reticulum

Question 1 Where do the ribosomes get synthesised?

Question 2 What are the main functions of Endoplasmic reticulum?

Question 3 Give the structure of Endoplasmic reticulum?

Question 4 Name two types of Endoplasmic reticulum?

Question 5 Define the term membrane biogenesis?

Endoplasmic Reticulum(ER)
ER is a large network of membrane bound tubes and sheets.

ER occurs in three forms
1)Cisternae (closed fluid filled sac)
2)Vesicles
3)Tubules

ER is of 2 types

1)Rough ER(ribosomes attached on its surface)
2)Smooth ER(ribosomes are not attached on its surface)
RBC do not contain ER.

Functions
1)It provides a pathway for distribution of nuclear material from one cell to other.
2)Certain enzymes present in SER synthesise fat,steroids,cholesterol.
3)RER help in transport of protein which are synthesised by ribosomes on their surface.
4)SER is involved in the process of detoxification(metabolises various toxic substances)
5)It function as cytoplasmic framework providing a surface for some of the biochemical activities of the cell.
6)Digestive enzymes of lysosomes are produced on RER.
7)Plasma membrane and other cellular membranes are formed on ER.
8)Proteins which are synthesised by the cell and then released into outer medium of the cell are called secretary proteins.These proteins are synthesised by RER.

SER help in the formation of fat molecules,lipids,cell membrane.This process is called membrane biogenesis.