The endoplasmic reticulum (ER) is an organelle in eukaryotes that forms an interconnected network of vesicles, tubules, and cisternae within cells. There are two types of endoplasmic reticulum: the rough and smooth endoplasmic reticulum. The rough endoplasmic reticulum synthesizes proteins while the function of the smooth endoplasmic reticula is to synthesize steroids and lipids; regulate calcium concentration, drug metabolism, as well as attachment of receptors on cell membrane proteins; and metabolize steroids (but not lipids) and carbohydrates. The sarcoplasmic reticula solely regulate calcium levels.

Rough Endoplasmic Reticulum Structure

The rough endoplasmic reticulum forms a branched reticulum that is expanding as the cell becomes more active in the synthesis of proteins. There are instances wherein the reticulum branches out and the cisternae dilate and forms large sacs that fill the cell. The main reason why the rough endoplasmic reticulum is referred as ‘rough’ is due to the ribosomes that it contains. The rough ER is covered with ribosomes and makes it looks bumpy under microscopic magnification. Amino acids are formed in the ribosomes and the information for the synthesis of certain proteins is taken from the DNA to the ribosome by the messenger RNA or mRNA mechanism. Such information is conveyed by the ribosomes and proteins are created accordingly with the exact sequence of amino acid with the aid of transfer RNA or tRNA. The rough endoplasmic reticulum is connected with the outer envelope of the nucleus of the cell.

Rough Endoplasmic Reticulum Function

The primary Rough Endoplasmic Reticulum function of the rough endoplasmic reticulum is the processing and the production of specific proteins at ribosomal sites, which will be exported later. The ribosomes in the rough ER perform their tasks and create proteins that will be sent to the rough endoplasmic reticulum to undergo advance processing. Its function involves the creation of two protein types: one is the type that toughens and is embedded into the reticulum membrane and other type is the membranes that are water-soluble, which after creation at ribosomal site, passes through the membrane and into the lumen.

The rough endoplasmic reticulum function does not end there; the proteins that enter it will be further processed inside. It is almost the same as folding a two dimensional box to make three dimensional protein box wherein carbohydrates are added. When the folding is complete, they are now ready to be delivered. The folding process is made possible by the chaperone proteins found in the lumen. The ready proteins will be transported to sites where they are needed. Such sites include Golgi apparatus, wherein advanced processing is applied.

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