Smooth Endoplasmic Reticulum
The SER is named as such because of its smooth surface. The surface of the SER is smooth because there are no ribosomes present on its surface. The SER is composed of a branching network of vesicles and tubules. These are important to the cell, since they help facilitate newly synthesized protein, and help to fold them properly. It also helps the cell maintain its volume, and prevents it from collapsing.
The SER is often found really close to the nuclear envelope, which is present inside each cell. There are a number of tasks that it performs.
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Rough Endoplasmic Reticulum
The RER is given its name because of its rough surface. It has a rough surface because of all the ribosomes present on its surface. Ribosomes are attached to the RER via the help of ribophorin, which is a glycoprotein receptor. However, this binding between the two is not a permanent one.
The RER looks like it is an extension of the nuclear envelope because of the way it is located next to it. Its main purposes is to synthesize protein.
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