write the functions of rough ER. (3 marks )
write the functions of rough ER. (3 marks )
Functions of the Rough Endoplasmic Reticulum The rough endoplasmic reticulum plays a number of roles within the cell, largely associated with protein synthesis. Polypeptides are synthesized, modified, folded into their correct 3-D shape and sorted towards an organelle or marked for secretion. It also plays an important role in modulating the response of cell to stress and in quality control for correct protein folding. When the number of unfolded proteins increases, cells alter their tubules:sheets ratio. This could arise from the greater area available within the sheets of the rough ER to rescue unfolded protein, or could reflect the need for the distinct proteome of the rough ER.
The rough ER’s proteome reflects its specific role within the cell. It contains enzymes involved in RNA metabolism that bind to and modify RNA. This is necessary since the organelle is involved in translating RNA into protein. It also contains proteins that recognize various signal sequences within a growing polypeptide, and aid in their translocation. Glycosylation enzymes and proteins that act as molecular chaperones that ensure proper folding of the synthesized polypeptides are also important proteins within this organelle. Occasionally, apoptosis is induced by the ER in response to an excess of unfolded protein within the cell. This function is mediated in consort with mitochondria.
The rough endoplasmic reticulum plays a number of roles within the cell, largely associated with protein synthesis. Polypeptides are synthesized, modified, folded into their correct 3-D shape and sorted towards an organelle or marked for secretion. It also plays an important role in modulating the response of cell to stress and in quality control for correct protein folding. When the number of unfolded proteins increases, cells alter their tubules:sheets ratio. This could arise from the greater area available within the sheets of the rough ER to rescue unfolded protein, or could reflect the need for the distinct proteome of the rough ER.
The rough ER’s proteome reflects its specific role within the cell. It contains enzymes involved in RNA metabolism that bind to and modify RNA. This is necessary since the organelle is involved in translating RNA into protein. It also contains proteins that recognize various signal sequences within a growing polypeptide, and aid in their translocation. Glycosylation enzymes and proteins that act as molecular chaperones that ensure proper folding of the synthesized polypeptides are also important proteins within this organelle. Occasionally, apoptosis is induced by the ER in response to an excess of unfolded protein within the cell. This function is mediated in consort with mitochondria.
