'How a Virus Finds a Host Essay\r'

'Introduction\r\n AIDS and the shuttle flu scram raised concerns about computer computer virus round outs in the public eye. Infectious transfer of virus also very often causes the parking argona cold. We be fit to tolerate or overcome the large majority of viruses, but roughly of them succeed in causing us to fall ill, steady to the heyday of death. Not every nonp atomic number 18il responds to a virus epidemic in the same carriage: some overpower the pathogen, opus an some other(prenominal)s succumb.\r\nA fundamental understanding of the temper of a virus preempt solve these app bent paradoxes; its chemical appliance of taking cling to in animateness waver is also relevant. It is worth noting at the outset that viruses hunt for all forms of plants and animals as militarys. Each type of virus has a particular preference of host. A virus is versatile and so-and-so change form with ease.\r\n elemental genetic structures and administrations\r\n A virus is a course of bridge betwixt a form of vitality and an inanimate object. All animate things ar make from permutations and combinations of four nucleic acids, adenine, cytosine, thymine, and guanine. Sequences of nucleic acids form genes. Genes are in sub habit banded in concert, to form chromosomes.\r\nThe nucleic acids are joined together by ribose abrasions. The last menti onenessd has one molecule of sugar absent. The structure is entwined in the form of double genus Helix coils privileged the gist of each vitality cells. The latter are grouped together in high forms of liveliness to form create from raw materials and organs. The nucleic acid structure inside each nucleus is called Deoxyribonucleic acid or deoxyribonucleic acid.\r\n desoxyribonucleic acid is used by deportment forms to plead Ribonucleic acids or ribonucleic acid. ribonucleic acid has ribose sugar with the oxygen molecule absent in DNA. ribonucleic acid has just one brink of nucleic acids, as opposed to two in DNA. RNA has uracil instead of thymine. RNA moves out from the nucleus to the cytoplasm of living cells. RNA is used to uprise proteins, which act as the materials of vivification forms. DNA and RNA physiology is at the heart of all life. It is a common system from unicellular life forms to human beings. Protein action by RNA and RNA production by DNA is the chemical basis of life. This is a process, which continues without ceasing from blueprint to death.\r\nInsidious nature\r\n We are now nominate to look at the nature and structure of a virus. A virus has a structure quasi(prenominal) to RNA (Lewin, 744). However, the host DNA does not give it. It also differs from RNA in that it whitethorn check a protective membrane made of protein.\r\nA virus is a kind of imposter. It finds a way inside a cell and abuses the host’s DNA to produce proteins of its own. Since a virus has no DNA, it does not qualify as a life f orm in the strict sense. However, as it able to use host DNA to produce protein, and since it has the skill to replicate, it shares an requirement property of living things.\r\n The fine eminence between a virus and a living cell with a nucleus could remain in the academic domain, were it not for the deleterious ability of a virus to threaten well-being and indeed life itself. A mitigating factor is that a virus merchantmannot lose on its own: it must constitute shelter within the nucleus of a living cell, and is exclusively dependant on the host DNA.\r\nCat and black eye\r\n high forms of life, much(prenominal)(prenominal) as human beings, do not surrender to virus attack without a urge, and they most often win. A virus enters a host through the medium of foreign living tissue. Bodily discharges such as sputum, blood, semen, and mucus are the most common agents of viral transfer between one living body and another. Transmission is routine if two me mbers of a species are involved.\r\nA virus whitethorn occasionally adapt from one genus, even an order, or a phylum to another. Thus, an avian virus move infect a mammal, even a human. It can jump from one fowl to another near inevitably. viruses know that they cannot always hope to find a host of the same species in which they currently trail (Watson et all, 1016).\r\nA virus is always on the seem of a new host for its use of the take host’s DNA can be fatal for that host. The virus allow for hurt no use for a dead host, and must and then find a new life to infect. It has highly-developed a great adaptive capability, and can countersink to the DNA of a new host, which may be an entirely different form of life in which it has existed before. A snicker flu virus in a chicken would like a hefty chicken in which it can spread. Should other chickens be scarce, it will try to infect some other bird it can find.\r\nIt will settle for a human if it can find no bird or other animal. It is worth repeating that the bird flu virus can move from one bird to another bird or from one bird to a human, only through ad-lib or nasal of anal discharge from the give and original host. Should the latter be isolated, then the virus is doomed to extinction with the death of its host. Infection is essential for viral transfer.\r\n Animal bodies, especially human beings have powerful and sophisticated systems to combat invading viruses. Should a human being touch and ingest some discharge from an infect host, the virus will turn over physical entry, but the body, which it has entered, will not take things lying down. Defense systems in humans and other animals are equipped to see that a scalawag pretending to be RNA has entered the body and is laborious to cheat the DNA to produce proteins for its own use.\r\n A virus tries to read the nucleic acid sequence in the DNA of all host that it finds. It then attempts to produce proteins of its own need and choice from the DNA it encounters (Heritage, Evans and Killington, 122). We should bear in mind that a virus is fundamentally an imposter in the garb of RNA. It tries to plant its RNA sequence in a manner such that the host DNA cannot see through the disguise.\r\n higher(prenominal) forms of animal life have defense cells in blood. Soldier cells try to capture foreign virus-loaded tissue as soon as it enters the host. These cells are called macrophages and they tally most invasions by literally swallowing the foreign bodies.\r\nThis mechanism is not necessarily comprehensive, and some particles of the foreign bodies may escape the macrophage confrontation. The sub-microscopic size of a virus meaning that a few members of an infectious source may escape the host body’s attention. Virus is then free to enter living cells of the host and start interaction with the DNA. The virus can break instantly that it now has a different DNA structure. It st arts studying the new nucleic acid sequence and sees it can replicate in the changed circumstances.\r\n It is now time for the lymphocytes in the host blood to take charge (Despopoulos and Silbernagl, 68)\r\n Lymphocytes are of two kinds, B and T. The latter specialize in fighting viruses. They recognize the production of unusual proteins, and detect the viral infection of cells. T lymphocytes kill cells infected by a virus, in a proffer to contain the infection. T lymphocytes are produced in the thymus. well-informed individuals have immense capacity for defense and can ward off a majority of virus attacks.\r\nA compromise often prevails with the T lymphocytes loving the fight against a virus, though it is unable to annul all traces of the virus in the host. Such a host then functions as a common carrier, living with a low intensity of virus attack without external symptoms of any medical condition. A carrier can infect another individual who may succumb to the viru s if its T lymphocyte system does not function well. Cancers of the lymphatic system and malnutrition are the primary reason for a host’s T lymphocytes to fail in protecting a host from virus attack.\r\n We must bear in mind, for the question that has prompted this document, that a virus does not have the luxury of choosing a host. It will take any available living cell and try to adjust to the DNA sequence it finds. Nature favors the host: the virus will generally fail to break the command, or will perish with the host cell whose code it has broken.\r\nImmunity\r\n Though anti-retroviral therapy has now entered the realm of reality, nature provides hosts with the capability to recognize a virus and the will to destroy cells infected by viruses. Nature balances such powers by making viruses highly adaptable. They can chop-chop change their own sequences of acids in bids to escape sensing and to survive. Viruses will also settle for sub-clinical situat ions in which they are able to survive without killing the host on which it depends.\r\n It follows that immunity is a key to fighting viruses. Higher forms of life are equipped with innate capabilities to fight viruses to the extent that the species can thrive, though some affinity of every population falls prey. Hygiene and equilibrise nutrition are the only things that most life forms need to defeat thieving viruses.\r\nWorks Cited\r\nDespopoulos, A and Silbernagl, S, Color Atlas of Physiology, Georg Thieme Verlag Stuttgart, 1991\r\nHeritage, J. G. V. Evans, and R. A. Killington, Introductory Microbiology, Cambridge University Press, 1996\r\nLewin, B, Genes, Oxford University Press, 1997\r\nWatson, J. D. Nancy H. Hopkins, Jeffrey W. Roberts. Joan A. Steitz and Alan M. Weiner, Molecular biological science of the Gene, The Benjamin/Cummings Publishing Company, Inc. (1998)\r\n \r\n'