ULTRA STRUCTURE OF BACTERIAL CELL

Microorganisms exist as either prokaryotes or eukaryotes. The prokaryotic cells are morphologically much simpler than eukaryotic cells. The prokaryotic cells lack internal membrane bound organelles that are present in the cytoplasm of eukaryotic cells...

Leia Mais

VIRUS

Virus literally means ‘poison’. They are also called as filterable molecules during olden days as they are able to pass through filter pores which do not permit bacteria to pass. They are the submicroscopic entities. Andre Luoff, a virologist and Nobel...

Leia Mais

SEXUAL REPORDUCTION IN BACTERIA

In bacteria sexual reproduction is of three types :Transformation : The process of uptake of a complete or fragment of a naked DNA molecule by a competent cell from the medium and incorporation of this molecule into recipient chromosome in a heritable...

Leia Mais

IMPORTANCE AND SCOPE OF MICROBIOLOGY AS A MODERN SCIENCE

Some organisms are very small and can’t be seen with the unaided human eye. Hence these small and invisible organisms is called MICROBIOLOGY.Organism with a diameter of 1mm or less are can’t be seen with the human eye. Hence these organisms are called...

Leia Mais

MICROBES AND THEIR DISTRIBUTION

Microorganisms are widespread and omnipresent. They live in water, air and soil. They also live in side the plants and animals. Microorganisms are widely employed in many industries connected with the manufacture of food, medicines, textiles and chemicals....

Leia Mais

IMPORTANCE OF MICROBIOLOGY

Microorganisms serve as specific agents for large scale chemical transformations, specially variety of geochemical changes. Winogradsky and Beijerink proved that microbes play important role in the Carbon cycle, Nitrogen cycle, Sulphur cycle etc. they...

Leia Mais

HISTORY OF MICROBIOLOGY

The first person who discovered microorganism was a Dutch merchant Anton Van Leeuwenhoek. He named them as animalcules or little animals. Later scientific experiments helped to disprove the theory of spontaneous generation. Lewis Pasteur stated that...

Leia Mais

MUTATION AND MUTAGENESIS

Refers to any heritable change in nucleotide sequence of a gene of the organisms irrespective of altered phenotypic expression of characters of the organisms. A gene codes for a protein, therefore, the physical and chemical properties of proteins...

Leia Mais

GENETICS OF TRANSPOSITION

The genes of transposase and resolvase i.e. tnpR and tnpR are identified by recessive mutations. The above enzymes accomplish the two stages of TnA mediated transposition. Like IS- type elements the transposition stage involves the ends of the elements....

Leia Mais

TRANSDUCTION

The transfer of genetic material from one cell to another by a bacteriophage is called transduction. The phenomenon of transduction was first discovered by Zinder and Lederberg while searching for sexual conjugation in Salmonella species.The infection...

Leia Mais

GENETIC NOTATION

If a bacterial cell synthesizes amino acid leucine, it is represented as Leu+, and if it does not it is denoted as Leu+. The symbol has capitalized (not italicized) the letters. It denotes that Leu- has...

Leia Mais

ORIGIN AND EVOLUTION OF GENETIC CODE

From the discussion of genetic code some important facts came into light as the degeneracy and universality of the genetic code. It may be supposed that present from of genetic code would have evolved...

Leia Mais