Cytoplasm
Cytoplasm was a gelatinous fluid that filled most s in biological lifeforms.

The Klingon retrovirus known as  nehret destroyed the cells of its host by attacking their cytoplasmic membranes. ()

The medical book Gray's Anatomy mentioned in chapter one that "in the higher organisms a cell may be defined as a nucleated mass of protoplasm of microscopic size. Its two essentials, therefore, are: a soft jelly-like material, similar to that found in the ovum, and usually styled cytoplasm, and a small spherical body embedded in it, and termed a nucleus. Some of the unicellular protozoa contain no nuclei…" ()

The biochemical analysis of a symbiogenetic orchid discovered in the Delta Quadrant by Tuvok and Neelix in 2372, which was later a contributing factor in the creation of Tuvix, was found to contain the same elements as many plants including chloroplasts, lysosomal enzymes, and cytoplasmic proteins. ()

In 2373, Doctor Bashir speculated that exposure to tetryon radiation damaged the cytoplasm of the infant Changeling, resulting in its failing life signs. ()

See also 
 Cytoplasmic lifeform
 Cytoplasmic matrix
 Cytoplasmic separator
 Cytoplasmic stimulator

External link 
 

Biochemical compounds