A virus is a pathogenic agent, a infections particle, consisting of a core of nucleic acid (DNA or RNA) enclosed in a protein shell. Viruses are, in general, much smaller than bacteria and have a much smaller genome. But their genetic material is of many varieties, unknown in cellular organisms. Some of these are discussed here. Bacteriophage φX174 which attacks [...]
In this article we will discuss about the organisation of DNA in bacteria. The DNA of bacteria, e.g. E. coli, is a covalently closed circular molecule. It forms the bacterial chromosome, though this chromosome is much simpler in structure and in level of organization than the eukaryotic chromosomes of plants and animals. Also, each bacterial cell normally has a single [...]
The following points highlight the top six repair mechanisms of damaged DNA. The repair mechanisms are: 1. Photo Reactivation 2. Excision Repair 3. Re-Combinational Repair Mechanism 4. Repair of DNA by Homologous Recombination 5. SOS Repair of Damaged DNA 6. Mismatch Repair. Repair Mechanism # 1. Photo Reactivation: We know that exposure of UV-irradiated bacteria immediately afterwards to visible light [...]