The animal cell endoplasmic reticulum typically comprises over half of the membranous content of the cell. In the synthesis, modification, folding, and transport of proteins, there are important and multiple functions done by Endoplasmic reticulum (ER). ER is a unremitting membrane structure that forms a sequence of compressed sacs within the cytoplasm of eukaryotic cells. ER is contained in all eukaryotic cells. The rough ER and smooth ER are two types of ER distinguished by distinction in particular physical and functional distinctiveness.
Animal Cell Endoplasmic Reticulum: Rough ER
The name comes from the outer (cytoplasmic) surface of this ER that is attached to the ribosomes that make rough appearance. It is present next to the cell nucleus with continuous membrane connecting the outer membrane of the nuclear envelope. The rough ER has ribosomes that help to synthesize proteins with a signal series that sends them to the animal cell endoplasmic reticulum for processing. Free ribosomes synthesize some proteins that are not bound to the ER membrane or sent to the nucleus and mitochondria. There is definite final destinations Proteins synthesized by the rough ER. Next to the ER there is the Golgi apparatus where some proteins are sent to it while others are kept in the ER. The Golgi apparatus secrete proteins to the cell membrane or to lysosomes while others are secreted outside of the cell. Proteins will be modified, folded, and assembled in rough ER lumen after transferred from ribosomes on rough ER from the Golgi apparatus.
Animal Cell Endoplasmic Reticulum: Smooth ER
It serves differently to rough ER and is not associated with ribosomes. The smooth ER aids in the production of new cellular membrane by synthesize cholesterol, lipids, and phospholipids. Animal cell endoplasmic reticulum also synthesizes steroid hormones from cholesterol. It helps the detoxification of damaging chemicals and drugs in cells of the liver. The cytoplasm of striated muscle cells is where the calcium ion concentration regulated by a specific type of smooth ER called the sarcoplasmic reticulum.
Created the first electron micrograph of a cell, cell biologists Albert Claude, Keith Porter, and Ernest Fullman described lace-like reticulum for the extremely complicated and tangled structure of the ER in 1945. The word endoplasmic reticulum to explain the organelle was introduced by Porter and partner Frances Kallman and Helen P. Thompson at the end of 1940s and near the beginning 1950s. Main distinctiveness of the animal cell endoplasmic reticulum was clarified later on by Porter associated with cell biologist George E. Palade.