A crude lysate is the solution produced when cells are destroyed by disrupting their cell membranes in a process known as cytolysis. Crude lysates are routinely produced in biochemistry and cell biology laboratories during the process of protein purification, although purified cellular organelles can also be retrieved from the solution. The first step in processing a crude lysate is often ultracentrifugation, which separates the solution into distinct bands containing organelles, membrane lipids, proteins, and nucleic acids. Cells in culture, stained for keratin (red) and DNA (green). ... Drawing of a cell membrane A component of every biological cell, the selectively permeable cell membrane (or plasma membrane or plasmalemma) is a thin and structured bilayer of phospholipid and protein molecules that envelopes the cell. ... Cytolysis is the lysis, or death, of cells due to the rupture of the cell membrane. ... This article or section does not cite its references or sources. ... Cell biology (also called cellular biology or cytology, from the Greek kytos, container) is an academic discipline that studies cells. ... Protein purification is the process of isolating proteins from a homogenate, which may comprise cell and tissue components, including DNA, cell membrane and other proteins. ... Schematic of typical animal cell, showing subcellular components. ... Differential centrifugation is a procedure in which the homogenate is subjected to repeated centrifugations each time increasing the centrifugal force. ... This article or section does not cite its references or sources. ... A representation of the 3D structure of myoglobin, showing coloured alpha helices. ... Schematic diagram of a double-stranded nucleic acid. ...