Definition: One of the specialized parts of a protozoan or tissue cell; these subcellular units include mitochondria, the Golgi apparatus, nucleus and centrioles, granular and agranular endoplasmic reticulum, vacuoles, microsomes, lysosomes, plasma membrane, and certain fibrils, as well as plastids of plant cells.
[G. organon, organ, + Fr. -elle, dim. suffix, fr. L. -ella]
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Examples: glitazone, GI cocktail, etc.