Long description

The figure consists of four parts, Figures 8a to d, that illustrate the typical arrangement of a transmission electron microscope and micrographs of a frog leukocyte and HeLa cell.

Figure 8a: a photo shows a tall cylindrical transmission electron microscope (TEM) with a binocular eyepiece near its base just above the detector. The transmission electron microscope shows the following labelled parts from top to bottom: electron source, sample, and detector.

Figure 8b: the typical arrangement of a transmission electron microscope has an electron source located at the top, emitting a beam of electrons that pass through a set of magnets acting as lenses, a sample positioned on a middle sample holder, and more magnets acting as lenses. The beam of electrons diverges and hits the fluorescent screen to form a highly magnified image, which is then recorded by the detector present at the bottom.

Figure 8c: a transmission electron micrograph of a frog leukocyte shows a large densely stained nucleus with a nucleolus in its core. The nucleus is surrounded by numerous small oval-shaped organelles labelled mitochondria and a horizontal stack of tubules and vesicles labelled Golgi apparatus residing in the lightly stained cytoplasm.

Figure 8d: a scanning electron micrograph of a HeLa cell shows dividing nuclei surrounded by the cell membrane. The cell membrane has several surface extensions. The scale bar reads 20 micrometres.