The lumen of the endoplasmic reticulum is the internal space enclosed within the network of tubules and cisternae (flattened sacs) of the organelle.

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The endoplasmic reticulum (ER) is a network of membranous tubules and flattened sacs called cisternae, all bounded by a single lipid bilayer. The ER is continuous with the nuclear envelope, and it is divided into two structurally and functionally distinct regions—the rough endoplasmic reticulum (RER) and the smooth endoplasmic reticulum (SER)—which serve as sites for synthesizing different cellular molecules.

Endoplasmic Reticulum

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Microbiology covers the scope and sequence requirements for a single-semester microbiology course for non-majors. The book presents the core concepts of microbiology with a focus on applications for careers in allied health. The pedagogical features of the text make the material interesting and accessible while maintaining the career-application focus and scientific rigor inherent in the subject matter. Microbiology’s art program enhances students’ understanding of concepts through clear and effective illustrations, diagrams, and photographs.

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The rough endoplasmic reticulum (RER) is a region of the endoplasmic reticulum characterized by ribosomes bound to the cytoplasmic side of its membrane. These ribosomes synthesize proteins destined for the plasma membrane, which are inserted directly into the RER membrane. Newly synthesized proteins are packaged into transport vesicles that bud off from the RER and travel to the Golgi apparatus for further processing, the plasma membrane, other organelle membranes, or out of the cell.

Rough Endoplasmic Reticulum

The smooth endoplasmic reticulum is responsible for producing lipids, carbohydrates and detoxification of the cell. The smooth endoplasmic reticulum does not contain ribosomes embedded in the membrane which gives it a smoother appearance. 

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