Principles of Microbiology 1st Edition PDF

Principles of Microbiology 1st Edition PDF Free Download

Genetic determinants have been shown to consist of deoxyribonucleic acid (DNA) and ribonucleic acid (RNA). Enzymes are synthesized under the direction of nucleic acids, and enzymes, thus synthesized, are responsible for essentially all processes that occur in microorganisms. Experiments with. both bacteria (pneumococci) and viruses (radioisotope tests) have established roles of nucleic acids as determinants in microbial variations. Microorganisms are excellent for genetic studies, primarily because of haploid conditions in many of them and the ability of observers to detect mutations easily and test very large populations in short time periods. Permanent changes in bacteria can be differentiated from induced temporary types by fluctuation and replica plate techniques. Changes in DNA structure are termed mutations, and they occur in genes of chromosomes. Each gene may have a multiplicity of mutable sites. Since codons code for amino acids, a missense mutation occurs when a codon that codes for a new amino acid replaces a codon of a DNA chain, and a nonsense mutation results from replacement with a codon that codes for no amino acid. An altered nucleotide sequence may be restored to its original order by a reverse mutation, or an altered nucleotide sequence may be compensated for through a suppressor mutation. Either the DNA structure or the manner in which RNA is read may be altered.

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Dr. Taimour is a dedicated medical professional and passionate advocate for international medical graduates seeking to pursue their dream of becoming a doctor abroad. With a wealth of experience and firsthand knowledge of the challenges and rewards of this journey, Dr. Harrison is committed to helping aspiring physicians navigate the complex world of medical licensure exams, such as the USMLE and PLAB, and find their path to success in foreign medical practice.