Lysis (/ˈlaɪsᵻs/ LY-səs; Greek λύσις lýsis, "a losing" from λύειν lýein, "to unbind") refers to the breaking down of the membrane of a cell, often by viral, enzymic, or osmotic (that is, "lytic" /ˈlɪtᵻk/ LIT-ək) mechanisms that compromise its integrity. A fluid containing the contents of lysed cells is called a lysate. In molecular biology, biochemistry, and cell biology laboratories, cell cultures may be subjected to lysis in the process of purifying their components, as in protein purification, DNA extraction, RNA extraction, or in purifying organelles.