The endoplasmic reticulum plays an important role in the biosynthesis, processing, and transport of proteins and lipids. Credit: Encyclopaedia Britannica/UIG/Getty Images Updated on
December 03, 2019 The endoplasmic reticulum (ER) is an important organelle in eukaryotic cells. It plays a major role in the production, processing, and transport of proteins and lipids. The ER produces transmembrane proteins and lipids for its membrane and many other cell components including lysosomes, secretory vesicles, the Golgi appatatus, the cell membrane, and plant cell vacuoles. Key Takeaways
The endoplasmic reticulum is a network of tubules and flattened sacs that serve a variety of functions in plant and animal cells. The two regions of the ER differ in both structure and function. Rough ER has ribosomes attached to the cytoplasmic side of the membrane. Smooth ER lacks attached ribosomes. Typically, the smooth ER is a tubule network and the rough ER is a series of flattened sacs. The space inside of the ER is called the lumen. The ER is very extensive extending from the cell membrane through the cytoplasm and forming a continuous connection with the nuclear envelope. Since the ER is connected with the nuclear envelope, the lumen of the ER and the space inside the nuclear envelope are part of the same compartment. Rough Endoplasmic ReticulumThe rough endoplasmic reticulum manufactures membranes and secretory proteins. The ribosomes attached to the rough ER synthesize proteins by the process of translation. In certain leukocytes (white blood cells), the rough ER produces antibodies. In pancreatic cells, the rough ER produces insulin. The rough and smooth ER are usually interconnected and the proteins and membranes made by the rough ER move into the smooth ER to be transferred to other locations. Some proteins are sent to the Golgi apparatus by special transport vesicles. After the proteins have been modified in the Golgi, they are transported to their proper destinations within the cell or exported from the cell by exocytosis. Smooth Endoplasmic ReticulumThe smooth ER has a wide range of functions including carbohydrate and lipid synthesis. Lipids such as phospholipids and cholesterol are necessary for the construction of cell membranes. Smooth ER also serves as a transitional area for vesicles that transport ER products to various destinations. In liver cells the smooth ER produces enzymes that help to detoxify certain compounds. In muscles the smooth ER assists in the contraction of muscle cells, and in brain cells it synthesizes male and female hormones. Eukaryotic Cell StructuresThe endoplasmic reticulum is only one component of a cell. The following cell structures can also be found in a typical animal eukaryotic cell:
Watch Now: What Is a Eukaryote?How does the structure of the rough ER relate to the function?Narration. The endoplasmic reticulum can either be smooth or rough, and in general its function is to produce proteins for the rest of the cell to function. The rough endoplasmic reticulum has on it ribosomes, which are small, round organelles whose function it is to make those proteins.
What is the structure of the rough endoplasmic reticulum?The RER is morphologically distinguishable by its series of convoluted, flattened like membrane sheets (called cisternae) that arise near the nucleus and extend across the cytoplasm. Sections of the cisternae contain ribosomes, held together by microtubules of the cytoskeleton.
What are the type of endoplasmic reticulum describe their structure and function?The two types of endoplasmic reticulum are : Rough Endoplasmic Reticulum: Their main function is produce proteins in the cells and ribosomes are attached to their surface. Smooth Endoplasmic Reticulum: Their main function is to produce lipids and also detoxify toxins in the body in the liver and kidney cells.
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