<em>A lysosome is a membrane-bound cell organelle that contains digestive enzymes. ... They break down excess or worn-out cell parts. They may be used to destroy invading viruses and bacteria. If the cell is damaged beyond repair, lysosomes can help it to self-destruct in a process called programmed cell death, or apoptosis.</em>
<span>The lysosomes are membrane-enclosed organelle, usually spherical. They contain a number of hydrolytic enzymes that are able to break down dfferent kind of molecules. However, to maintain the optimal conditions for enzymes to perform their function, pH in the lysosomes must bi acidic and thus maintained between 4.5 and 5.0. Apart from hydrolytic enzymes, the lysosomes contain substances involved in cell signaling and energy metabolism. </span>
