A nucleotide is a compound, which can form a polynucleotide chain by the union of nitrogenous bases and sugar-phosphate group. Monomers of nucleotide units are connected via a covalent phosphodiester bond. Nitrogenous bases, i.e. purines and pyrimidine, are attached via weak hydrogen bonds. The bases link with a deoxyribose pentose sugar via an N-glycosidic bond. …
The bright-field microscopy produces an image with a coloured specimen having lightened background. Generally, the microorganisms do not absorb light, but the organisms can absorb the light after staining. The optical lens, i.e. condenser lens and the path of light coming from the light source illuminator produce a bright-field image with higher contrast and magnification. …
The continuous culture is an open cultivation process, in which the cell growth is maintained in the continuous mode of operations. It works as an open cultivation system, in which the fresh nutrient medium is continuously added into the culture vessel rather than recycling and reuse of the nutrients or substrate. There is an inlet pump …
The active site of an enzyme is the region, which shows the highest metabolic activity by catalysing the enzyme-substrate complex into the products. The active site is found deep inside the enzyme, which resembles a hole or small depression. An active site is a region combining the specific substrate molecule with the enzyme and thus …
Watson and Crick model of DNA provides one of the best ways to demonstrate the structure of double-helix DNA. A DNA is a polymer composed by the combination of several monomer units (deoxyribonucleotides) linked by the phosphodiester bond. In the discovery of DNA, many scientists have contextualized the structure of DNA, its components and composition …
Meselson and Stahl experiment gave the experimental evidence of DNA replication to be semi-conservative type. It was introduced by the Matthew Meselson and Franklin Stahl in the year 1958. Matthew Meselson and Franklin Stahl have used E.coli as the “Model organism” to explain the semiconservative mode of replication. There are three modes of replication introduced …
Hershey and Chase experiment give practical evidence in the year 1952 of DNA as genetic material using radioactive bacteriophage. Griffith also explained the transformation in bacteria and concluded that the protein factor imparts virulence to the rough strain, but it was not proved to be genetic material. Avery, Macleod and McCarthy further studied the Griffith …
Transfer RNA is an RNA type that acts as the intermediary element, and plays a significant role in the loading and transferring amino acids to the site of protein synthesis, i.e. Ribosome. The t-RNA first decodes the information or the nucleotide sequences carried by the m-RNA. Therefore, t-RNA also plays a major role in translating …
Agglutination reaction is an immunological assay, which results in the specific antigen and antibody reaction in vitro. Agglutination purely refers to the clumping or aggregation of the particles. As a result of agglutination, a cross-linked structure or lattice appears in the form of visible aggregates. Agglutination reaction is a sensitive, easy and cost-effective method to carry …
A precipitation reaction is a test involved in the serology, for the qualitative and quantitative detection of antigens and antibodies. It is a reaction, where the soluble reactants (antigen and antibody) convert into an aggregated form. The sensitivity of the precipitation reaction is comparatively less than the other immunoassay reactions. For the precipitation reaction, polyclonal …