Final answer:
To slice cells to 50-100nm for electron microscopy, cells are embedded in resin, dehydrated, sectioned with an ultramicrotome, and stained with heavy metals for TEM imaging.
Step-by-step explanation:
To slice a cell into a very narrow thickness of 50-100nm, significantly smaller than the cell's initial thickness of 10 microns, scientists use a technique in preparation for electron microscopy. This requires the cells to be embedded in a plastic resin, dehydrated with a graded series of ethanol solutions, and then finally sectioned using a sophisticated device known as an ultramicrotome. The thin sections are then mounted on grids and stained with heavy metals like uranyl acetate or osmium tetroxide, which contrast with the cellular structures when viewed under a transmission electron microscope (TEM).