Cells in tissue culture exhibit a dazzling array of colors when stained with multiple fluorescent probes and imaged with a confocal laser scanning microscope. The digital image presented below illustrates a cluster of living cells captured with the aid of fluorescent probes and laser scanning confocal microscopy.

Islands of Color Specimen: Cell Culture Technique: Fluorescence (Multiple Labels)

Two major classes of cells are prokaryotes and eukaryotes, which are similar in that they both contain DNA, RNA, ribosomes, a similar metabolism, and they are both protected from the outside environment by a thin membrane. Eukaryotes, however, are generally about ten times the size of prokaryotes, and they are also equipped with a nucleus, and membrane-bound organelles that perform specialized functions within the cell.