The rough endoplasmic reticulum It is an organelle found in the cells of eukaryotic organisms. It is made up of an interconnected network of flat sacks or encapsulated tubes in the shape of small flat bulging sacks. These membranes are continuous and are attached to the outer surface of the cell nucleus..
The endoplasmic reticulum can be found in all eukaryotic cells, except red blood cells and sperm. It should be noted that eukaryotic cells are those that have a cytoplasm contained by a membrane and have a defined nucleus. These cells form the tissues of all animals and a wide variety of plants..
There are two types of endoplasmic reticulum, rough and smooth. The rough reticulum is surrounded by other organelles called ribosomes, which are responsible for synthesizing proteins.
This type of reticulum is especially prominent in certain cell types, such as hepatocytes, where protein synthesis occurs actively. (BSCB, 2015)
The rough endoplasmic reticulum has numerous functions within the cell. These functions include protein transformation and transport. In particular, it is responsible for carrying these proteins to the Golgi apparatus. There are some other proteins, such as glycoproteins that move across the reticular membrane..
This rough reticulum is also responsible for marking the proteins it carries with a guaranteed sequential signal into the lumen. Other proteins are directed outside the reticulum, so that they can be packed into vesicles and expelled from the cell through the cytoskeleton..
In synthesis, the rough endoplasmic reticulum can be seen as the transport system used by eukaryotic cells to mobilize the proteins contained in them when they need to be moved. Helping its synthesis, folding and quality control.
A cell can be defined as a set of membranes. In this way, the endoplasmic reticulum provides 50% of the membranes found in animal cells. However, it is also present in plant cells and is essential for the manufacture of lipids (fats) and proteins..
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There are two main types of endoplasmic reticulum, the smooth and the rough. Both are membranes that fulfill very similar functions, however, the rough reticulum has a different shape thanks to the fact that its surface is striated and is closer to the nucleus of the cell and the Golgi apparatus..
In this way, the rough reticulum has the appearance of small bulging discs, while the smooth reticulum looks like a tubular membrane without streaks. What gives the rough reticulum that appearance are the ribosomes that are attached along its membrane (Studios, 2017).
The rough endoplasmic reticulum is an organelle that is present in all eukaryotic cells and whose main task is to process proteins and move them from the nucleus to the ribosomes along their surface.
While ribosomes must build amino acid chains, the reticulum is responsible for moving this chain into the cisternal space and the Golgi apparatus, where the more complex proteins can be terminated..
Both animal and plant cells have the presence of both types of endoplasmic reticulum. However, these two types remain separate depending on the organ where the cell is located..
Since cells whose main function is the synthesis and production of proteins will have a larger rough reticulum, while those that are responsible for producing fats and hormones will have a higher concentration of smooth reticulum.
It is believed that once proteins are processed by the reticulum, they pass into the Golgi apparatus in small, bubble-shaped vesicles..
However, some scientists argue that the reticulum, cell nucleus membrane, and Golgi apparatus are so closely located that these vesicles do not even exist, and substances are simply filtered from one place to another within. this complex.
Once the proteins pass through the Golgi apparatus, they are transported by the reticulum to the cytoplasm to be used inside the cell.
The rough endoplasmic reticulum is an extensor organelle composed of flat, bulging, and hermetic sacs located adjacent to the nuclear membrane..
This type of reticulum is called “rough” because it has a striated texture on its outer surface, which is in contact with the cytosol and ribosomes..
Ribosomes adjacent to the rough endoplasmic reticulum are known as membrane-bound ribosomes and are firmly attached to the cytosolic side of the reticulum. Approximately 13 million ribosomes are present in the rough endoplasmic reticulum of any liver cell.
In general, this type of reticulum is uniformly distributed within any cell, however, it can be seen in a higher concentration near the nucleus and the Golgi apparatus of any eukaryotic cell. (SoftSchools.com, 2017)
The ribosomes found in the rough endoplasmic reticulum have the function of making many proteins. This process is known as translation and takes place mainly in the cells of the pancreas and the digestive tract, places where a high volume of proteins and enzymes must be made.
The rough endoplasmic reticulum works in conjunction with membrane-bound ribosomes to take polypeptides and amino acids from the cytosol and continue the protein-making process. Within this process, the reticulum is responsible for giving a "label" to each protein during the early stage of its formation..
Proteins are produced by the plasma membrane, the Golgi apparatus, secretory vesicles, lysosomes, endosomes, and the endoplasmic reticulum itself. Some proteins are deposited in the lumen or empty space inside the reticulum, while others are processed within it..
In the lumen, proteins are mixed with groups of sugars to form glycoproteins. Some can also be mixed with metal groups during their passage through the endoplasmic reticulum, generating polypeptide chains that join to give rise to hemoglobin..
Within the lumen of the rough endoplasmic reticulum, proteins are folded to form biochemical units of complex architecture, which are encoded to make more complex structures..
A comprehensive protein quality control process also takes place in the lumen. Each of them is checked for possible errors.
In case of finding a misfolded protein, the lumen will reject it and will not allow it to continue in the process of forming more complex structures.
The rejected proteins are stored in the lumen or are recycled and eventually re-broken down into amino acids. For example, a type A pulmonary emphysema is generated when the quality control that takes place in the lumen of the rough endoplasmic reticulum, continuously rejects proteins that have not been folded correctly..
The misfolded protein will receive as a result an altered genetic message that will be impossible to read in the lumen..
This protein will never leave the lumen of the reticulum. Today, studies have been conducted that relate this process to possible failures caused in the body under the presence of HIV.
There is a type of cystic fibrosis that occurs when an amino acid (phenylamine) is missing in a specific place in the protein manufacturing process.
These proteins can work well without the amino acid, however, the lumen detects that there is an error in that protein and rejects it, preventing it from advancing within the formation process..
In this case, the patient with cystic fibrosis completely loses the ability to build more elaborate proteins, since the lumen does not allow poor quality proteins to pass through (Benedetti, Bánhegyi, & Burchell, 2005).
In most cases, the proteins are transferred to the Golgi apparatus to be 'finished'. In this place they are transported to vesicles or are possibly located between the surface of the endoplasmic reticulum and the Golgi apparatus. Once finished, they are sent to specific locations within the body (Rogers, 2014).
Structurally, the rough endoplasmic reticulum is a network of membranes that can be found anywhere in the cell and connect directly with the nucleus..
Membranes are slightly different from cell to cell, as how the cell works determines the size and structure of the reticulum it needs.
For example, some cells such as prokaryotic, sperm or red blood cells do not have any type of endoplasmic reticulum..
Cells that synthesize and release a higher concentration of proteins and, on the other hand, need to have a larger endoplasmic reticulum.
This is clearly seen in cells of the pancreas and liver, where the cells have a large rough endoplasmic reticulum to be able to synthesize proteins (Inc., 2002).
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