Difference between rough endoplasmic reticulum and smooth endoplasmic reticulum Class 9
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 Introduction on Rough and Smooth Endoplasmic ReticulumRough and smooth endoplasmic reticulum are two types of organelles found in the cytoplasm of eukaryotic cells. Rough endoplasmic reticulum has a roughened appearance due to the presence of ribosomes on its surface, while smooth endoplasmic reticulum lacks ribosomes. The primary function of the endoplasmic reticulum is to synthesize proteins. The rough endoplasmic reticulum is responsible for synthesizing proteins that will be exported from the cell, while the smooth endoplasmic reticulum synthesizes proteins that will be used within the cell. What is an endoplasmic reticulum?The endoplasmic reticulum (ER) is a membranous network of tubes and sacs that forms a continuous internal surface in the cytoplasm of eukaryotic cells. The ER is involved in a variety of biochemical activities, including the synthesis of proteins, the transport of proteins and lipids, and the storage of calcium ions. The ER also plays a critical role in the folding of proteins into their correct three-dimensional shapes. Types of ERPERP systems can be classified into three types: Functions of Rough Endoplasmic ReticulumThe rough endoplasmic reticulum (RER) is a type of organelle found in the cytoplasm of eukaryotic cells. It is a network of interconnected tubules and sacs that performs several important functions, including protein synthesis and transport, lipid synthesis and transport, and calcium ion storage. The smooth endoplasmic reticulum (SER) is a membranous network of interconnected tubes and sacs that forms a continuous system throughout the cytoplasm of eukaryotic cells. The primary function of the smooth endoplasmic reticulum is to modify and package proteins for secretion from the cell. The SER also helps to maintain the cell’s fluidity by pumping calcium ions in and out of the cell. Functions of SERMsSERMs are a class of drugs that act as estrogen receptor modulators. This means that they can mimic the effects of estrogen in some tissues, while blocking its effects in others. This gives them a variety of potential therapeutic applications, including the treatment of breast cancer, osteoporosis, and menopausal symptoms. Overall functions of endoplasmic reticulumThe endoplasmic reticulum (ER) is a membranous network of tubes and sacs that occupies most of the cell cytoplasm. It is a site of protein synthesis and folding and is also involved in the transport of materials within the cell. The ER has two main functions: (1) to synthesize proteins and (2) to transport materials. Difference between RER and SERRER stands for “regional express railway” and SER stands for “Spanish railway network”. The main difference between the two is that RER is specific to France, while SER is specific to Spain. SER also has a much larger network than RER. There is a significant difference between RER and SER. RER stands for “relative effective resistance.” It is a measure of the resistance offered by a particular circuit to the flow of alternating current. SER stands for “series equivalent resistance.” It is a measure of the resistance offered by a particular circuit to the flow of direct current.
Smooth and rough ER are two types of endoplasmic reticulum, which develop an interconnected system consisting of membrane-bound channels in the cytoplasm of the cell. ER is a membrane-enclosed organelle found only in eukaryotic cells. The ER is composed of a membrane network called cisternae. Its rough appearance is given by the bound ribosomes on its surface. Rough ER synthesizes and stores proteins. Smooth ER, on the other hand, helps in the storage of proteins and lipids. The main difference between smooth and rough ER is that smooth ER lacks bound ribosomes whereas rough ER is bound with ribosomes. This article explains, 1. What is Smooth ER What is Smooth ERSmooth ER is a type of endoplasmic reticulum, which lacks surface-bound ribosomes. But some smooth ERs consist of ribosome-bound surfaces. They are called transitional ER. Structure of Smooth ERUsually, the smooth ER is connected to the nuclear envelope. They also consist of tubules which are located near the cell periphery. These tubes are branched to form a network which is reticular in appearance. Dilated areas like sacs can also be formed. This reticulum of ER increases the surface area devoted to the action of the ER. Figure 1: Appearance of the Endoplasmic Reticulum Functions of Smooth ERSome specialized cells consist of a lot of smooth ER. The smooth ER synthesis lipids, phospholipids and steroids in these cells. Lipid synthesizing cells can be found in testes, ovaries and sebaceous glands. Transport vesicles containing lipids and proteins can be found near the smooth ER. These vesicles detach from the ER and move into the Golgi apparatus. Other than the lipid synthesis, smooth ERs are involved in the metabolism of carbohydrates and steroids. They detoxify alcohol, drugs and natural metabolism products. They also regulate calcium ion concentration in muscle cells. However, smooth ER contains glucose-6-phosphate in order to convert glucose-6-phosphate into glucose, which involves in gluconeogenesis. What is Rough ERRough ER is the other type of endoplasmic reticulum found with surface-bound ribosomes. This is the ER which synthesizes proteins. Structure of Rough ERThe rough appearance of the rough ER is given by the ribosomes bound to its surface. Ribosome binding site on the rough ER is referred to as the translocon. Ribosomes are not permanently bound organelles with ER. They constantly bind and release from the membrane. Golgi apparatus is a large, double-membrane sheet formed by the ER. Proteins are shuttled between ER and Golgi apparatus via membrane-bound vesicles. Figure 2: ER and Golgi Apparatus Functions of Rough ERRibosomes bind to the ER while the formation of a specific protein-nucleic acid complex in the cytoplasm. This complex is formed during the beginning of the translation of mRNA, which belongs to a protein in the secretory pathway. The translation begins in a free ribosome. The first 5-30 amino acids encode the signal peptide. The signal peptide on the growing amino acid chain is recognized by signal recognition particle (SRP). Then, the ongoing translation is paused, and the ribosome complex binds to the translocon on rough ER. The translation is continued again in order to form the amino acid chain. The nascent protein enters the RER lumen. Inside the lumen, further modifications are acquired by post-translational modifications. The signal peptide is removed by the enzyme, peptidase. After removing the signal peptide, bound ribosomes are released back to the cytoplasm. Some ribosomes are continuously associated with the ER, and they are called non-translating ribosomes. Other than the synthesis and processing of proteins, rough ER is involved in the synthesis of lysosomal enzymes and integral membrane proteins. N-linked glycosylation is also initiated at the rough ER. Difference Between Smooth and Rough ERRibosomesSmooth ER: Ribosomes are absent in smooth ER. Rough ER:Ribosomes are present in rough ER LocationSmooth ER: Smooth ER is mainly found near the cell membrane. Rough ER: Rough ER is mainly found near the cytoplasm. OriginSmooth ER: Smooth ER originates from rough ER by shedding the ribosomes. Rough ER: Rough ER originates from nuclear membranes. CompositionSmooth ER:Smooth ER is mainly composed of tubules. Rough ER: Rough ER is mainly composed of cisternae. FunctionSmooth ER: Major function is to synthesis lipids. They also store lipids and proteins. Rough ER: Major function is to synthesize and store proteins. LocalizationSmooth ER:Smooth ER is mainly present in lipid forming cells such as adipocytes, interstitial cells of the testis, glycogen storing cells in the liver, adrenal cortex cells, muscle cells, leukocytes, etc. Rough ER: Rough ER is mainly present in protein forming cells such as pancreatic acinal cells, goblet cells, antibody producing plasma cells, Nissl’s granules of nerve cells, etc. ConclusionER is considered as an interconnected system consisting of membrane-bound channels in the cytoplasm. Both smooth and rough ER play a role in the synthesis and storage of macromolecules. Smooth ER produces lipids. They also store lipids and proteins. On the contrary, rough ER synthesizes proteins and stores them. The presence of ribosomes, bound on the surface of the rough ER lets them synthesize proteins. Therefore, the main difference between smooth and rough ER is in the presence or absence of ribosomes on their surfaces. Reference: Image Courtesy: What are the differences between rough and smooth endoplasmic reticulum?The rough ER, studded with millions of membrane bound ribosomes, is involved with the production, folding, quality control and despatch of some proteins. Smooth ER is largely associated with lipid (fat) manufacture and metabolism and steroid production hormone production. It also has a detoxification function.
What is the function of RER and SER Class 9?(a) Enzymes packed in the Lysosomes are synthesized by the RER (rough endoplasmic reticulum). (b) Rough endoplasmic reticulum and smooth endoplasmic reticulum produce lipids and proteins respectively.
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