Microsome

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microsome

[′mī·krə‚sōm]
(cell and molecular biology)
A fragment of the endoplasmic reticulum.
A minute granule of protoplasm.

Microsome

 

a fragment in the endoplasmic network (bubbles about 1,000 angstroms diameter), formed when cells are destroyed during the homogenization of animal and plant tissues. The microsome fraction of the homogenate is isolated by differential centrifugation. There are two types of microsomes: smooth-surfaced and rough-surfaced (as a result of the distribution of ribosomes on the latter). Before the technique of separating cellular homogenates was perfected, the microsome fraction also included mitochondria.