Outline the steps involved in preparing a specimen for viewing by light microscopy. State the usefulness of the Gram Stain. This is the typical type of microscope used in science labs because these scopes are relatively inexpensive compared to those described below. Named darkfield because the cells appear translucent against a dark black background, analogous to a streetlight seen at night. After several minutes, the slide is viewed.
Invisible cytoplasm is colored by allowing inward diffusion of colored dye molecules, that is stain.
A second, differently colored stain, also known as a counterstain. Fluorescent molecules that glow under UV light. Cell or tissue specimens are incubated in OsO4 before processing for TEM viewing. OsO4 oxidizes molecules of cells to create contrast on TEM specimens. This is a highly carcinogenic stain, so gloves must be worn during its usage.