| endoplasmic | Referring to the endoplasm. (05 Mar 2000) |
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| endoplasmic reticulum | <cell biology> Membrane system that ramifies through the cytoplasm. The membranes of the endoplasmic reticulum are separated by 50-200 nm and the cisternal space thus enclosed constitutes a separate compartment. The Golgi region is composed of flattened sacs of membrane that together with endoplasmic reticulum and lysosomes constitute the GERL system. See: smooth endoplasmic reticulum, rough endoplasmic reticulum. (18 Nov 1997) |
| endoplasmic reticulum, rough | A type of endoplasmic reticulum (er) where polyribosomes are present on the cytoplasmic surfaces of the er membranes. This form of er is prominent in cells specialised for protein secretion and its principal function is to segregate proteins destined for export or intracellular utilization. (12 Dec 1998) |
| endoplasmic reticulum, smooth | A type of endoplasmic reticulum lacking associated ribosomes on the membrane surface. It exhibits a wide range of specialised metabolic functions including supplying enzymes for steroid synthesis, detoxification, and glycogen breakdown. In muscle cells, smooth endoplasmic reticulum is called sarcoplasmic reticulum. (12 Dec 1998) |
| agranular endoplasmic reticulum | Endoplasmic reticulum that is lacking in ribosomal granules; involved in synthesis of complex lipids and fatty acids, detoxification of drugs, carbohydrate synthesis, and sequestering of Ca++. Synonym: smooth-surfaced endoplasmic reticulum. (05 Mar 2000) |
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| granular endoplasmic reticulum | Endoplasmic reticulum in which ribosomal granules are applied to the cytoplasmic surface of the cisternae; involved in the synthesis and secretion of protein via membrane-bound vesicles to the extracellular space. Synonym: chromidial substance, ergastoplasm, rough-surfaced endoplasmic reticulum. (05 Mar 2000) |
| rough endoplasmic reticulum | <cell biology> Membrane organelle of eukaryotes that forms sheets and tubules. Contains the receptor for the signal receptor particle and binds ribosomes engaged in translating mRNA for secreted proteins and the majority of transmembrane proteins. Also a site of membrane lipid synthesis. The membrane is very similar to the nuclear outer membrane. The lumen contains a number of proteins that possess the C terminal signal KDEL. (17 Dec 1997) |
| rough-surfaced endoplasmic reticulum | Endoplasmic reticulum in which ribosomal granules are applied to the cytoplasmic surface of the cisternae; involved in the synthesis and secretion of protein via membrane-bound vesicles to the extracellular space. Synonym: chromidial substance, ergastoplasm, rough-surfaced endoplasmic reticulum. (05 Mar 2000) |
| smooth endoplasmic reticulum | <cell biology> An internal membrane structure of the eukaryotic cell. Biochemically similar to the rough endoplasmic reticulum, but lacks the ribosome binding function. Tends to be tubular rather than sheet like, may be separate from the rough endoplasmic reticulum or may be an extension of it. Abundant in cells concerned with lipid metabolism and proliferates in hepatocytes when animals are challenged with lipophilic drugs. Acronym: SER (18 Nov 1997) |
| smooth-surfaced endoplasmic reticulum | Endoplasmic reticulum that is lacking in ribosomal granules; involved in synthesis of complex lipids and fatty acids, detoxification of drugs, carbohydrate synthesis, and sequestering of Ca++. Synonym: smooth-surfaced endoplasmic reticulum. (05 Mar 2000) |
| transitional endoplasmic reticulum | <cell biology> Region at the boundary of the rough endoplasmic reticulum and the Golgi. Transport vesicles are responsible for the transfer of secretory proteins from this part of the rough endoplasmic reticulum to the Golgi system. (18 Nov 1997) |