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(cell and molecular biology)
A specialized subcellular structure, such as a mitochondrion, having a special function; a condensed system showing a high degree of internal order and definite limits of size and shape.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.



a part of the body of a unicellular organism, or protozoan, that performs any one of various functions. Organelles are especially diverse and complex in Infusoria and Flagellata. There are several types of organelles. Skeletal and support organelles protect the organism from mechanical, chemical, and other harmful effects (for example, the shells of Sarcodina and Infusoria). There also are locomotor and contractile organelles (for example, flagella, cilia, and myonemes); sensory, or receptor, organelles (for example, photosensitive ocelli); and attack and defense organelles (for example, in Infusoria, the rod-shaped formations known as trichocysts, which are discharged from the body). Digestive organelles capture, conduct, and digest the food (for example, the digestive vacuoles of Infusoria). There are also excretory and secretory organelles (for example, the pulsating vacuoles of Infusoria). The term “organelle” is often used as a synonym for “organoid.”

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.
References in periodicals archive ?
One is stochastic-mode that involves the rearrangement of all organelles before cytokinesis.
The compartments, called membraneless organelles, are found throughout the cell.
(15) However, it proved very difficult to study the cellular and molecular mechanisms of organelle division in eukaryotes for the following reasons.
Scientists at The Rockefeller University have discovered that it depends on whether tiny organ-like structures known as organelles are allocated properly within the dividing stem cell.
Biologists and biology educators face this issue when communicating about any sort of biological structure, from organelles to whole organisms.
Mitochondria are minute organelles inside living cells, floating apart from the nucleus in the cytoplasm.
The resulting functional enzyme complex, made of a nontoxic polymer, "almost mimics an organelle," says Yunfeng Lu, a professor of chemical and biomolecular engineering at the University of California, Los Angeles, who led the research with Cheng Ji, a professor of biochemical and molecular biology at the University of Southern California.
However, I do like his analogies, especially the mangrove tree of life and his description of the relationship between a cell and its organelles as rooms aboard a ship.
Furthermore, a family of calcium-dependent cysteine proteases--calpains--occur in abundance in the lens and play a crucial role in organelle degradation and programmed cell death [29-31].
Fun Fact: This structure is an organelle, or specialized unit of a cell, commonly found in plants.
There is some disagreement among cell biologists concerning the definition of an organelle. For the purpose of this book, an organelle is a distinct entity within the cell that performs a particular function as a compartmentalization of enzymes.