endoplasmic reticulum membrane, where they remain. After passage
Compartments and functional organization from the rough endoplasmic reticulum, proteins remain in membrane-
bound cytoplasmic organelles such as lysosomes, become incorporated
The cytoplasm consists of the cytosol, a gel-like material enclosed by
into new plasma membrane, or are secreted by the cell. Some carbohy-
the cell or plasma membrane. The cytosol is made up of colloidal pro-
drates are also synthesized by enzymes within the cavities of the rough
teins such as enzymes, carbohydrates and small protein molecules,
endoplasmic reticulum and may be attached to newly formed protein
together with ribosomes and ribonucleic acids. The cytoplasm contains
(glycosylation). Vesicles are budded off from the rough endoplasmic
two cytomembrane systems, the endoplasmic reticulum and Golgi
reticulum for transport to the Golgi as part of the protein-targeting
apparatus, as well as membrane-bound organelles (lysosomes, peroxi-
mechanism of the cell.
somes and mitochondria), membrane-free inclusions (lipid droplets,