The larger dark purple structure is the nucleolus. This picture shows an electron micrograph of a nucleus. The short white arrows are pointing to nuclear pores. Note the appearance of eu- and heterochromatin, and the nucleolus. Heterochromatin stains more densely than euchromatin, but they are both forms of chromatin.

Nucleus. The nucleus of a pancreatic β cell (which synthesizes large amounts of the protein insulin) as seen by transmission electron microscopy (TEM). Switch between the grayscale and color images (see above) to identify these components of a nucleus. Chromatin (blue) - DNA bound to histones and other proteins. Exists in two forms:

Below is a collection of electron micrographs with labelled subcellular structures that you should be able to identify. Also, be sure to observe any electron micrographs which are made available in the laboratory by the instructor.

Transmission electron microscopy allows the direct visualization of the individual components of the cell nucleus. Unlike fluorescence microscopy, which relies upon the use of fluorescent probes to tag structures, TEM is capable of visualizing the structures themselves.

In this article we will discuss about:- 1. The Electron Micrograph of Mitochondria 2. The Electron Micrograph of Golgi Complex 3. The Electron Micrograph of Endoplasmic Reticulum 4. The Electron Micrograph of Lysosomes 5. The Electron Micrograph of Plastids 6. The Electron Micrograph of Nucleus. Contents: 1. The Electron Micrograph of Mitochondria.

High resolution transmission electron micrograph of Halteria showing both the large macronucleus with nuclear pores, dense heterochromatin bodies and nucleolus, and the small micronucleus. CIL:11027 NCBI Organism Classification

The following grayscale electron micrographic images are available [file sizes average 100 to 160k]: Anatomy-Histology main menu.

The electron micrograph in (b) shows a roughly spherical cell with its darkly staining (electron-dense) nucleus toward the left. Within the nucleus are several large and irregularly-shaped, pale (electron-lucent) areas, which are the nucleoli.

Unlike the transverse section thru the middle of a nucleus seen in EM 007 Nucleus, this is a tangential section thru the edge of a nucleus as seen by transmission electron microscopy (TEM). The surface of most nuclei are slightly irregular with invaginations. This micrograph is from a tangential section across one of these invaginations.

Fig. 31C: Transmission Electron Micrograph of a Nucleus. Transmission electron micrograph of a pancreatic acinar cell from a bat. Note the nuclear membrane, nucleolus, and nuclear pores (arrows). Endoplasmic reticula is also seen.