Chapter 2, Problem 1TQ

Summary Introduction

To review:

The bacterial features that can be studied by the following techniques of microscopy: light microscopy, fluorescence microscopy, scanning electron microscopy, transmission electron microscopy.

Introduction:

The human eye can resolve things that are up to 1 millimeter in size. In order to resolve the objects below this size, human eyes need equipment that has greater resolving power. Microscopes are equipment that are used to imagine the objects that cannot be resolved by the eyes.

There are various types of microscopes that are used for imaging the bacteria and other microscopic entities. All microscopes operate on the same principles of physics, refraction of light leading to magnification. The illumination and magnification in several microscopes can be obtained from the light while some use electron beams. The bacterial features that can be studied by the above-mentioned techniques of the microscopy are listed below:

1. Light microscopy: The shape of the bacteria can be revealed by using light microscopy. The bacteria that form the chain can also be detected using this technique. The cell wall of the Gram-positive and Gram-negative bacteria can also be examined under light microscopy.

2. Fluorescence microscopy: Fluorescent dyes are used in this technique. These dyes can bind up with the specific macromolecules present in a particular region of the cell. Thus, the specific position of the organelles can be revealed by this technique. This technique can also be used to trace various ongoing biological processes in the cell-like replication.

3. Scanning electron microscopy : A beam of electron is used in this technique in order to magnify the image. It can help in detecting the surface details of the bacteria. The composition of the external surface of the cell can be revealed by this technique.

4. Transmission electron microscopy: This technique is similar to the bright light microscope except for an electron source from a tungsten filament instead of a light source. It is used to reveal internal details of microorganisms like the presence of flagellum. The cell organelles can also be revealed by using this technique of microscopy.