Lysosome
lysosome
"A class of morphologically heterogeneous cytoplasmic membrane-bound vesicle in animal and plant tissues characterized by their content of a wide variety of glycoprotein hydrolytic enzymes active at an acid pH and the structure-linked latency of these enzymes. The intracellular functions of lysosomes depend on their lytic potential. The single unit membrane of the lysosome acts as a barrier between the enzymes enclosed in the lysosome and the external substrate. The activity of the enzymes contained in lysosomes is limited or nil unless the vesicle in which they are enclosed is ruptured. Such rupture serves to digest exogenous material, such as bacteria, as well as effete organelles of the cells and is supposed to be under metabolic (hormonal) control."