Protein Sorting In Endoplasmic Reticulum
Background
Cell division in a eukaryotic cell comprises of a series of complex process that ultimately lead to new daughter cells. While the cell undergoes division all the organelles have to undergo duplication so that they can be passed onto the daughter cells.
The cell needs information from old organelles to synthesize new organelles. This process takes place during cell division, when the old organelles increase in size (enlargement occurs), due to incorporation of new molecules. These organelles then finally divide into two with the cell forming daughter organelles.
However in endoplasmic reticulum, golgi apparatus and the nuclear envelope the vesicles break apart and the new daughter organelle are formed when they fuse.
All these processes require an appropriate amount of lipids and proteins. As these compounds are essential in…show more content… This sequence is also involved in the initial movement of these proteins towards the endoplasmic reticulum.
In the endoplasmic reticulum the proteins that gain entry are usually threaded across the endoplasmic reticulum membrane before the synthesis of the polypeptide chain can be completed. Hence for this purpose the endoplasmic reticulum membrane contains the protein synthesizing ribosome. These ribosomes are usually present on the surface of the rough endoplasmic reticulum.
Two types of ribosomes are found in the cytosol of the cell:
1. Membrane bounded ribosomes
These are present on the outer regions of the nuclear membrane and attached to the cytosolic side of the endoplasmic reticulum membrane. The translocated proteins are manufactured by these ribosomes.
2. Free ribosomes
Nuclear DNA encoded proteins are manufacture by the free proteins. These ribosomes are present freely, unattached to membrane of any