write a short note on location of endoplasmic reticulum
Answers
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.