In this article we will discuss about the meaning and functions of capsule. Meaning of Capsule: Some of the bacterial cells are surrounded by the extracellular polymeric substances (EPS) which are commonly called capsule or glycocalyx. It forms an envelope around the cell wall and can be observed under light microscope after special staining technique (Fig.4.2). The presence of capsule [...]
In this article we will discuss about the X-ray crystallographic studies of DNA. In 1920, the basic chemical composition of nucleic acid was elucidated through the efforts of P.A. Levene. In 1940, for the first time W.T. Astbury gave first three dimensional structure of DNA model studied through X-ray crystallography. He concluded that its flat nucleotides get stacked to form [...]
In this article we will discuss about:- 1. Meaning of Chemo-taxis 2. Demonstration of Chemo-taxis 3. Chemotactic Behaviour of Bacteria. Meaning of Chemo-Taxis: Chemo-taxis is the movement of bacteria towards chemical attraction and away from chemical repellants. Bacteria are attracted towards the nutrients such as sugars and amino acids, and are repelled by harmful substances and bacterial wastes. They also [...]