Question

wirte a short note on endoplasmic reticulum

Answer 1

It  is a type of organelle in the cells of eukaryotic organisms that forms an interconnected network of flattened.the structure of the endoplasmic reticulum is a network of membranes called cisternae.The word reticulum, which means "network", was applied to describe this fabric of membranes.Endoplasmic reticulum has two types, rough endoplasmic reticulum (RER) and smooth endoplasmic reticulum (SER). It  is the transportation system of the eukaryotic cell, and its proteins are contained within it until they are needed to move. 

Answer 2

Write a short note on Endoplasmic reticulum with a neat labeled diagram.

ANSWER

Endoplasmic Reticulum is three-dimensional networks of intracellular membranes. It is present in all eukaryotic cells. In young meristematic cells, ER is very much developed. In spermatocytes, ER is represented by a few vacuoles. Cells actively synthesising proteins like liver, fibroblast and pancreatic cells have abundant ER.

1. ER is formed of three types of elements.

Cisternae :

- They are sacs like unbranched structures.

- It lies in stacks or piles parallel to each other. These cisternae in the stack are interconnected with each other.

- Cisternae contain transmembrane Glycoprotein Ribophorin 2, they bind with larger subunits of the ribosome.

- Cytosolic spaces are present between Cisternae.

Tubules :

- These are irregular branched tubular structures.

- They form a network along with other elements.

Vesicles :

- These are oval, rounded vacuole-like elements.

- It is often isolated in the cytoplasmic matrix.

2. There is two type of ER :

Smooth ER or Smooth Endoplasmic Reticulum: Ribosome is not present in SER. It is generally peripheral in position & connected with the plasma membrane.

Rough ER (RER) or Rough Endoplasmic Reticulum: RER is present in the Ergastoplasm. RER is generally internal in position & are connected with the nuclear envelope.