Lysosomes are membrane bound sacs that are filled with enzymes, manufactured by the golgi apparatus and are usually spherical in shape. Lysosomes function as the digestive system of the cell, serving both to breakdown material taken up from outside the cell and to digest obsolete components of the cell itself.  Lysosomes break down cellular waste products and debris from outside the cell into simple compounds, which are transferred to the cytoplasm as new cell-building materials.