Cytoplasm

The cytoplasm is the gel-like substance residing within the cell membrane holding all the cell's internal sub-structures (called organelles), outside the nucleus. All the contents of the cells of prokaryote organisms (such as bacteria, which lack a cell nucleus) are contained within the cytoplasm. Within the cells of eukaryote organisms the contents of the cell nucleus are separated from the cytoplasm, and are then called the nucleoplasm. The cytoplasm is about 70% to 90% water and usually colourless.