Answer Show Hint: Rough endoplasmic reticulum is playing an important role in the synthesis of protein. The main difference between the rough endoplasmic reticulum and smooth endoplasmic reticulum is that RER consists of ribosomes that are responsible for its rough nature and synthesis of protein. Complete answer: Differences between RER and SER are as follows:
Additional Information: -Ribosomes are the protein factory of the cell hence RER functions for protein synthesis. -Retinal cells, nerve cells, muscles, plasmodesmata (desmotubules) all consist of SER. -SER functions for the formation of microbodies. -RER, SER together with Golgi bodies, lysosomes, and vacuoles (in plants) form the endomembrane system. -The term endoplasmic reticulum was given by Porter and was discovered by Porter and Thomson. -Cytoplasm around Golgi bodies is called a zone of exclusion as it’s devoid of any organelle. -SER is responsible for the formation and breakdown of glucose.Note: -Spherosomes and glyoxysomes are the two main microbodies formed by SER. -In the smooth endoplasmic reticulum, there is a specialized type of structure known as sarcoplasmic reticulum which regulates the calcium ion concentration in striated muscle cells.
Quick look Rough ER (RER) is involved in some protein production, protein folding, quality control and despatch. It is called ‘rough’ because it is studded with ribosomes Smooth E R (SER) is associated with the production and metabolism of fats and steroid hormones. It is ‘smooth’ because it is not studded with ribosomes and is associated with smooth slippery fats. To view a micrograph of ER interpreted using the Gridpoint cross-hairs device, click here. CELLS NEED THE ROUGH AND THE SMOOTH Think of a cell as a “multitude of membranes” we said in an earlier section. This statement certainly applies to the endoplasmic reticulum an organelle found in eukaryotic cells.
There are two types of endoplasmic reticulum: rough endoplasmic reticulum (rough ER) and smooth endoplasmic reticulum (smooth ER). Both types are present in plant and animal cells. The two types of ER often appear as if separate, but they are sub-compartments of the same organelle. Cells specialising in the production of proteins will tend to have a larger amount of rough ER whilst cells producing lipids (fats) and steroid hormones will have a greater amount of smooth ER. Part of the ER is contiguous with the nuclear envelope. The Golgi apparatus is also closely associated with the ER and recent observations suggest that parts of the two organelles, i.e. the ER and the Golgi complex, are so close that some chemical products probably pass directly between them instead of being packaged into vesicles (droplets enclosed within a membrane) and transported to them through the cytoplasm ROUGH ENDOPLASMIC RETICULUM This is an extensive organelle composed of greatly convoluted but flattish sealed sacs, which are contiguous with the nuclear membrane. It is called ‘rough’ endoplasmic reticulum because it is studded on its outer surface (the surface in contact with the cytosol) with ribosomes. These are called membrane bound ribosomes and are firmly attached to the outer cytosolic side of the ER About 13 million ribosomes are present on the RER in the average liver cell. Rough ER is found throughout the cell but the density is higher near the nucleus and the Golgi apparatus. Ribosomes on the rough endoplasmic reticulum are called ‘membrane bound’ and are responsible for the assembly of many proteins. This process is called translation. Certain cells of the pancreas and digestive tract produce a high volume of protein as enzymes. Many of the proteins are produced in quantity in the cells of the pancreas and the digestive tract and function as digestive enzymes. The rough ER working with membrane bound ribosomes takes polypeptides and amino acids from the cytosol and continues protein assembly including, at an early stage, recognising a ‘destination label’ attached to each of them. Proteins are produced for the plasma membrane, Golgi apparatus, secretory vesicles, plant vacuoles, lysosomes, endosomes and the endoplasmic reticulum itself. Some of the proteins are delivered into the lumen or space inside the ER whilst others are processed within the ER membrane itself. In the lumen some proteins have sugar groups added to them to form glycoproteins. Some have metal groups added to them. It is in the rough ER for example that four polypeptide chains are brought together to form haemoglobin. Protein folding unit Protein quality control section Rigorous quality control plays a part in cystic fibrosis From Rough ER to Golgi SMOOTH ENDOPLASMIC RETICULUM Smooth ER is more tubular than rough ER and forms an interconnecting network sub-compartment of ER. It is found fairly evenly distributed throughout the cytoplasm. It is not studded with ribosomes hence ‘smooth’ ER. Smooth ER is devoted almost exclusively to the manufacture of lipids and in some cases to the metabolism of them and associated products. In liver cells for example smooth ER enables glycogen that is stored as granules on the external surface of smooth ER to be broken down to glucose. Smooth ER is also involved in the production of steroid hormones in the adrenal cortex and endocrine glands.
Image created with biorender.com The rough endoplasmic reticulum is a type of endoplasmic reticulum consisting of flattened sacs, studded with protein-synthesizing particles termed ribosomes on the outer surface.
Read Also: Endoplasmic Reticulum (ER)- Definition, Structure, Functions, and DiagramSmooth Endoplasmic Reticulum (SER)Smooth endoplasmic reticulum (SER) is a type of endoplasmic reticulum consisting of tubular vesicles that lack ribosomes on the outer surface and is involved in the synthesis and storage of lipids.
Key Differences (Rough endoplasmic reticulum vs Smooth endoplasmic reticulum)
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