Smooth vs Rough Endoplasmic Reticulum | SER vs RER
Cell is the basic functional unit of life, and it is composed of few organelles inside. Endoplasmic reticulum is one of the very important structures in a cell, and there are two major types of it known as smooth and rough. Endoplasmic reticulum is often abbreviated as ER; hence, smooth type is denoted as SER and the rough type is symbolized as RER. There are interesting differences in structures and functions between these two types and, this article summarizes most of those.
Smooth Endoplasmic Reticulum
Smooth endoplasmic reticulum (SER) is named because of its smooth surface. The surface is smooth because there are no ribosomes. The structure of SER is a branching network of tubules and vesicles. These networks structures are important to facilitate newly synthesized proteins to be folded correctly. In addition, it contributes to maintain the volume of a cell at a certain level.
Usually, the location that SER is mostly found is close to the nuclear envelope. SER plays important roles in many cellular metabolic processes in a cell such as lipid and steroid synthesis, carbohydrate breakdown, and regulating the calcium levels. Additionally, the detoxification of drugs and steroid metabolism have also been performed with SER in cells. SER assists the cellular functions such as gluconeogenesis with the presence of glucose-6-phosphatase enzyme. The network structure provides an increased surface area to store and put into effect some important enzymes. The products of those processes are also stored inside the SER structures. SER has been proven for its importance to attach receptors on proteins in the cell membrane. Furthermore, SER functions differently depending on the type of tissue, but above mentioned functions are usual at most of the times.
Rough Endoplasmic Reticulum
Rough endoplasmic reticulum (RER) is the ER with ribosomes present on the surface. Because of the presence of ribosomes, the whole structure appears rough, and it is so named. Ribosomes are attached to the surface with ribophorin, a glycoprotein receptor. In addition, this binding is not permanent, but it keeps bound and released always, except while a protein is being synthesized where the ribosome is always bound to ER.
The structure of RER is a large network of tubules and vesicles. It should be noted that the RER surface is connected with the nuclear envelope or in other words, it looks like an extension of the nuclear envelope. The basic functions of RER include the facilitation of sites to synthesize protein, a reserve of cell membranes, and formation of lysosome enzymes. In addition, its structure contributes to maintain the stability to the body of the cell.
What is the difference between Smooth and Rough Endoplasmic Reticulum?
• RER has ribosomes on the surface but, not in SER. Therefore, RER is observed as rough while SER as smooth in the microscope.
• SER is attached to the nuclear envelope while RER is continuous with the nuclear envelope.
• RER contributes for the protein synthesis more than SER does.
• RER mainly functions as providing home for ribosomes to produce, whereas SER serves several other functions such as detoxification, metabolism, and steroid synthesis.
• The structure of RER is larger than SER.
• RER is a reserve of cell membranes, as it provides extra cell membrane portions whenever is needed, but SER does not often do it.