Staining
Most cells are almost transparent and it is very hard to distinguish any structures. To better visualize cells and their specific components you can use chemicals that stain certain structures. Before the stain can be applied to the sample, the specimen needs to be prepared.
Usually one or several of these additional procedures is required to stain cells:
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Dehydration - Replacing the water within the sample with some other chemical
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Permeabilization - dissolving cell membranes to allow larger dye molecules to penetrate inside the cells
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Fixation - involves several techniques, such as creating chemical bonds between proteins to increase their rigidity.
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Mordant application - a substance that forms a strong complex with the dye and the tissue
There are many different stains, following a list of the stains used in the virtual labs: