Endoplasmic reticulum discovered by

Share this • Share on Facebook: Press release Share this content on Facebook Facebook • Tweet: Press release Share this content on Twitter Twitter • Share on LinkedIn: Press release Share this content on LinkedIn LinkedIn • Share via Email: Press release Share this content via Email Email this page Press release KAROLINSKA INSTITUTET October 1974 Albert Claude, Christian de Duve and George E. Palade for their discoveries concerning “the structural and functional organization of the cell”. The last 30 years have seen a new discipline, cell biology, appear and develop into one of the more important biological areas. It is true that the cell could be studied with the aid of the light microscope earlier since the middle of the 19th century, but its power in resolving structure and composition of the components in the cell responsible for its activities is very limited. A decisive improvement in the possibilities of studying the role of the cellular components was brought about by two different procedures, both introduced at The Rockefeller Institute in New York during the mid-forties. One was the application of procedures for using the electron microscope, already available since several years, for the study of cellular structures with a resolution far above that of the light microscope. The other was the development of procedures for the chemical study of the components that could be seen under the electron microscope. For this purpose tissues or cells were carefully homogeni...

Cells have extensive sets of intracellular membranes, which together compose the endomembrane system. The endomembrane system was first discovered in the late 1800s when scientist Camillo Golgi noticed that a certain stain selectively marked only some internal cellular membranes. Golgi thought that these intracellular membranes were interconnected, but advances in microscopy and biochemical studies of the various membrane-encased organelles later made it clear the organelles in the endomembrane system are separate compartments with specific functions. These structures do exchange membrane material, however, via a special type of transport. Today, scientists know that the endomembrane system includes the endoplasmic reticulum (ER), Golgi apparatus, and lysosomes. Vesicles also allow the exchange of membrane components with a cell's plasma membrane. Membranes and their constituent proteins are assembled in the ER. This organelle contains the enzymes involved in lipid synthesis, and as lipids are manufactured in the ER, they are inserted into the organelle's own membranes. This happens in part because the lipids are too hydrophobic to dissolve into the cytoplasm. Similarly, transmembrane proteins have enough hydrophobic surfaces that they are also inserted into the ER membrane while they are still being synthesized. Here, future membrane proteins make their way to the ER membrane with the help of a signal sequence in the newly translated protein. The signal sequence stops tra...

endoplasmic reticulum (ER), Membrane system within the cytoplasm of a eukaryotic cell ( see eukaryote), important in the synthesis of proteins and lipids. The ER usually makes up more than half the membrane of the cell and is continuous with the outer membrane of the nuclear envelope ( see nucleus). There are two distinct regions of ER: the rough ER, or RER (so called because of the protein-synthesizing ribosomes attached to it), and the smooth ER (SER), which is not associated with ribosomes and is involved in the synthesis of lipids and the detoxification of some toxic chemicals.