Chapter 8: Microscopy & Lab Techniques

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Lab techniques have evolved tremendously over the past 100 years, and this has allowed scientists to learn an incredible amount about the natural world. In doing so, scientists have pushed the limits of research, developed new medications and technologies, and even cloned organisms!

In this chapter, we will discuss some of the most important advancements in biological laboratory technologies and techniques relevant for the DAT.

Overview of Microscopy

Microscopy is an important technique in biology because it allows scientists to learn more about life by magnifying objects they could not otherwise see with their naked eye. Before we discuss more about the two main types of microscopy, we will discuss the processes of fixation and staining:

Fixation is the process of getting cells to ‘stick’ on a microscope slide, such that the cell is preserved in its most life-like state. Another benefit of cell fixation is that it makes it easier for cells to hold onto any stain that is applied.

There are several types of fixation, including heat fixation and chemical fixation. Heat fixation will be the most important for the purposes of the DAT, so we will discuss it in some detail:

First, freshly harvested cells will be placed on one side of a microscope slide. Then, the underside of that same slide will be passed over a Bunsen burner flame. This causes the slide to heat up, which ‘glues’ the cells on the slide. Heat fixation also preserves cells because the heat causes cell processes to stop - i.e. it kills them.