Rough Endoplasmic Reticulum
The rough endoplasmic reticulum is made up of membranes which have ribosomes attached to it. This gives it the rough appearance. This is contrary to the smooth endoplasmic reticulum which does not have these membrane bound ribosomes. This means that the rough endoplasmic reticulum is responsible for the production of polypeptides that are about to be taken through the membrane to be post-modified.
Rough endoplasmic reticulum is an organelle found in eukaryotic cells. Its main function is to produce proteins.
It is made up of cisternae, tubules and vesicles. The cisternae are made up of flattened membrane disks, which are involved in the modification of proteins. They are held together by the cytoskeleton. The rough endoplasmic reticulum also contains a perinuclear space, which is the space between the inner and outer phospholipid membrane. The membrane is continuous to the nuclear membrane. However, it isn’t continuous to the Golgi apparatus. Proteins are transferred from the Rough endoplasmic reticulum to the Golgi apparatus via membrane-bound vesicles.
The reason why it is rough endoplasmic reticulum is because of the ribosomes attached to the endoplasmic reticulum. These ribosomes are constantly being attached and detached from the ER because they are not part of the stable organelle. They attach when the ribosome begins to synthesis a protein which is going to be secreted (secretory pathway).
Rough endoplasmic reticulum has a number of functions. One of the main functions of the rough endoplasmic reticulum is to produce and process specific proteins. These are the exported through the secretory pathway. After they are exported via membrane vesicles, they can be sent to the Golgi Apparatus to be further processed or to organelles. They can even be exported to outside the cell and into another part of the body. Ribosomes also create proteins which are embedded into the rough endoplasmic reticulum for further processing (integral membrane proteins). Water soluble proteins are created too, which are exported through the membrane into the lumen.