Microbiology Notes | Biochemistry,Immunolgy,Cell biology

 Eukaryotes and prokaryotes: Definition of Prokaryotic Cells                      P rokaryotes (pro-KAR-ee-ot-es) (from Old Greek pro- before + karyon nut or kernel, referring to the cell nucleus, + suffix -otos , pl. -otes ; also spelled "procaryotes") are organisms without a cell nucleus (= karyon), or any other membrane-bound organelles. Most are unicellular, but some prokaryotes are multicellular. Generalized structure of Prokaryotic cell consists of the following: Glycocalyx:  This layer function as a receptor, the adhesive also provide protection to the cell wall. Nucleoid:  It is the location of the genetic material (DNA), large DNA molecule is condensed into the small packet. Pilus:  Hair like hollow attachment present on the surface of bacteria, and is used to transfers of DNA to other cells during cell-cell adhesion. Mesosomes:  ...

Basic Microbiology - Koch's postulates                          T he first direct demonstration that bacteria cause disease came from the study of anthrax by the German physician Robert Koch (1843–1910).The postulates were formulated by Robert Koch and Friedrich Loeffler in 1884 and refined and published by Koch in 1890.1905 he was awarded the Nobel Prize in Physiology or Medicine. Koch’s postulates are the criteria that establish a causative relationship between a microbe and a disease, there are four exceptions to Koch’s postulates. Koch Experiment             K och injected healthy mice with material from diseased animals, and the mice became ill. After transferring anthrax by inoculation through a series of 20 mice, he incubated a piece of spleen containing the anthrax bacillus in beef serum. The bacteria grew,...

  Bacterial Morphology - Bacteria Size, Shape and Arrangement Definition Bacteria are microscopic unicellular organism they are true living organism that belongs to the kingdom prokaryotes.   (Singular: bacterium) are a large group of unicellular microorganisms. They lack membrane-bound organelles like those found in eukaryotes. They are extremely tiny thus they cannot be seen individually unless viewed through microscope. When cultured on agar, the bacteria grow as colonies that contain many individual cells. These colonies appear as spots of varying size, shape and colour, depending on the microorganism. Bacterial Size In general, bacteria are between 0.2 and 2.0 um - the average size of most bacteria. Research studies have shown their size to play an important role in survival over time. There are some that hold this to range between 1 and 10 micrometers. E. coli bacteria range between 1.1 and 1.5 um in diameters, B. anthracis range betwe...

 Spontaneous Generation From earliest times, people had believed in spontaneous generation— that living organisms could develop from nonliving matter.  This view finally was challenged by the Italian physician Francesco Redi (1626–1697), who carried out a series of experiments on decaying meat and its ability to produce maggots spontaneously. Experiment     In his experiment he used covered and uncovered containers of meat, Redi clearly demonstrated that the generation of maggots by decaying meat resulted from the presence of fly eggs, and meat did not spontaneously generate maggots, as previously believed.              The container which is remain in uncovered condition ,it's produces maggots on the decaying meat because the meat is remain in direct contact with he air.that is why it is contaminated with the flying eggs.            Th...