In an animal cell, the cytoplasm is a semi-liquid substance that holds all the cell's organelles except the nucleus. It also acts as a repository for amino acids, sugars and other important nutrients used in the regular life of the cell. Finally, the cytoplasm stores a cell's waste until it is flushed from the cell.
The cytoplasm comprises three main parts. The main part, which makes up more than 50 percent of a cell's volume, is the cytosol. This gel-like substance is composed of water, dissolved enzymes and salts. The second major component of the cytoplasm is the cell's organelles. These structures, such as the mitochondria, the endoplasmic reticulum and the Golgi apparatus, perform important metabolic and reproductive parts of the cell's life cycle. The organelles are suspended in the cytosol and get the nutrients that they need to perform their functions from that substance. Finally, the cytoplasm contains indissoluble elements, such as starches and lipid droplets, that help store important chemicals. Important cellular functions, such as cell division, glycolysis and protein synthesis, take place in the cytoplasm, and it is also host to the cytoskeleton, which provides structure to the animal cell. Unlike in plant cells, the cytoplasm in animal cells does not contain chloroplasts.