A structure consisting of the cell membrane and all of the intracellular components, but devoid of a cell wall. This (removal of cell’s outer wall) can be done to plant cells via treatment with cell-walldegrading enzymes or electroporation. Under specific conditions (e.g., electroporation), certain DNA sequences (genes) prepared by man, can enter protoplasts. The cell then incorporates some or all of that DNA into its genetic complement (genome), and produces whatever product the newly introduced gene codes for. In the case of plant protoplasts, whole plants can be regenerated from the (genetically engineered) protoplasts, resulting in plants that produce whatever product(s) the introduced gene(s) codes for.
The entire contents of a cell.
In bacteriology, the sphere remaining after gram-positive bacteria are lysed and their cell walls destroyed. Gram-negative bacteria retain a partial cell wall and are called spheroplasts.