Question

Explain Endoplasmic recticulam.........????????? ​

Answer 1

Endoplasmic Reticulum (ER)
It is a network of fluid-filled interconnecting membranous tube - like structures covering the most part of the cytoplasmic matrix. It occurs in three forms: cisternae (closed fluid-filled sacs), vesicles and tubules. The ER membrane is similar in structure to the plasma membrane. It communicates with the plasma membrane and also with the nuclear envelope. (Rough) Endoplasmic reticulum is of two types:

(i) Rough endoplasmic reticulum (RER): With its outer surface are attached ribosomes which synthesise proteins. It is well developed in protein synthesising cells, like pancreatic and liver cells.

(ii) Smooth endoplasmic reticulum (SER): It is found with rough ER. Its surface is smooth, devoid of ribosomes. It is found in glycogen-rich regions. These secrete lipids.


Functions:

The main functions of ER are as follows:

(i) ER forms a network in cytoplasmic matrix, giving mechanical support to
the cell.

(ii) It functions as an intracellular transport system for various substances ER collects synthetic products of cell and then transports them outside the cell. It also transports the RNA and nucleoproteins from the nucleus to the cytoplasm where protein synthesis occurs.

(iii) Protein synthesis occurs on the surface of rough ER by ribosomes. These proteins are either used within the cell or exported outside the cell.
(iv) Synthesis of lipids in collaboration with Golgi complex occurs on the surface of smooth ER. Synthesis of lipoproteins and glycogen occurs on smooth ER in liver cells.

(v) Smooth ER membrane contains enzymes for lipid synthesis and for lipid soluble drugs and other harmful compounds. These enzymes detoxify the above drugs and make them water soluble so that they may be excreted in urine.

Answer 2

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Endoplasmic Reticulum Definition. The endoplasmic reticulum (ER) is a large organelle made of membranous sheets and tubules that begin near the nucleus and extend across the cell. ... The ER contains special membrane-embedded proteins that stabilize its structure and curvature.