Human Infections in the Year 2009 Essay Example | Topics and Well Written Essays - 3250 words

Human Infections in the Year 2009 - Essay Example These impacts could range from just interfering to the normal metabolic functions of the host organisms to the instant cause of death to the host. There are many types of infection in the human contexts such as parasitic, bacterial, or viral infections. Many of these infections caused many human lives throughout the ages. From the bubonic plague to the acquired immune deficiency syndrome, infections played an important involvement in humans' history, religion, and evolution. The breakthrough of the microscope gave way to the discovery of microorganisms. There are two types of cell that could be found in the living world, the prokaryotic and the eukaryotic cells. Prokaryotic cells are primarily characterized by the absence of nuclear membrane within the cell while eukaryotic cells have nuclear membrane that separates the deoxyribonucleic acid (DNA) from the other organelles in the cytoplasm of the cell. Bacteria are microorganisms believed to be the first life forms on earth. Prokaryotes could be eubacteria or true bacteria, or archaebacteria. The difference between eubacteria and archaebacteria are the absence of muramic acid in the cell wall of archaebacteria, the presence of ester linkage between lipids in eubacterial cell membrane and ether linkage in archaebacteria, the different structural types of ribonucleic acid (RNA) polymerase present between the two, the resistance of archaebacteria to chloramphenicol, streptomycin, and kanamycin, and the hig h tolerance of archaebacteria to strive in extreme physico-chemical factors of environments such as hot or cold temperature, high salinity, and others as compared to eubacteria. Furthermore, some other differences between prokaryotes and eukaryotes are the presence of cell wall in most prokaryotes which is composed of mucopeptide, and polysaccharide protein, while, most eukaryotic cell wall is polysaccharide. The absence of mitochondria and chloroplast organelle in prokaryotes is also observed. The presence of plasmids- a circular extra-chromosomal double stranded DNA capable of self replicating and could transfer genetic information to nuclear DNA for the cellular survival- in prokaryotes is commonly observed although some eukaryotes could have plasmids, the occurrences are very rare. The ability of prokaryotes to reduce sulfur, fix atmospheric nitrogen to N2, produce their own food with the utilization of inorganic nutrients, and the ability to store poly-B-hydroxybutyrate (PHB) is detected (Pandolfi et al. 2007). Among the infections known to science, the bacterial infections are the most common. Different kinds of diseases are caused by different kinds of bacteria. Eubacteria or true bacteria or simply bacteria could be classified into groups through their shapes, sizes and staining technique used to view them. There are six basis of classifying bacteria. These are shape, Gram reaction, atmosphere, spores, biochemistry, and serology test. Bacterial shape could be cocci, spiral, or bacilli. Cocci are spherical, bacilli are long and thin shape, and spiral could vary in wavelength and curve. On the other hand, classifying bacteria through Gram reaction is based on its cell wall properties. The Gram reaction could result to Gram-negative or