Describe the process of replication in viruses?
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'Myxoviruses'\nName is from the Greek 'myxa' = mucus!\n\nInfluenza pandemics have been recognized for several centuries. In the last century, H. influenzae (and other bacteria) were cited as the causal agent, but in 1933 Smith, Andrewes and Laidlaw isolated the virus in ferrets. In the 1940's (still pre-tissue culture, primitive immunology, few other viruses known), the characteristic property of haemagglutination was observed, followed by the discovery that the virus could be propagated in embryonated hens eggs (after adaptation) - this made influenza one of the best studied viruses during this period. More viruses with similar properties were added to the group, until it was split into two families in the 1970s, the Paramyxoviridae and the Orthomyxoviridae: \n  \n\n \n\nCharacteristic: Orthomyxoviridae: Paramyxoviridae: \nSize: Particle: 80-120nm (highly pleiomorphic) \nCore diameter: 9nm \n Particle: 125-250nm (somewhat pleiomorphic) \nCore diameter: 14-20nm \n \nReplication: Nuclear Cytoplasmic \nGenome: Segmented (-)sense RNA Non-segmented (-)sense RNA \n\n \n\nGroup V: (-)sense RNA Viruses \n \nFamily\n\n(Subfamily) \n Genus \n Type Species \n Hosts \n \nOrthomyxoviridae \n Influenza A virus \n Influenza A virus \n Vertebrates \n \nInfluenza B virus \n Influenza B virus \n Vertebrates \n \nInfluenza C virus \n Influenza C virus \n Vertebrates \n \nIsavirus\n Infectious salmon anemia virus\n Vertebrates \n \nThogotovirus \n Thogoto virus \n Vertebrates \n \n\n\nIt is believed that all (-)sense RNA viruses may have evolved from a common ancestor - all replicate their genomes by a common mechanism. However, the Mononegvirales have non-segmented genomes with similar organization and control of gene expression.\n\nOrthomyxoviruses\nMorphology:\nInfluenza virus particles are highly pleiomorphic (variable), mostly spherical/ovoid, 80-120nm diameter, but many forms occur, including long filamentous particles (up to 2000nm long x 80-120nm diameter). Different strains of virus vary in their tendency to form filaments - this property maps to the matrix protein.\n\n\n© Paul Digard, Dept Pathology, University of Cambridge.  The outer surface of the particle consists of a lipid envelope from which project prominent glycoprotein spikes of two types:\n\nhaemagglutinin (HA), a 135Å trimer \nneuraminidase (NA), a 60Å tetramer \nThe inner side of the envelope is lined by the matrix protein.\n\nThe particles are relative labile (half-life a few hours @ R.T.), not resistant to drying, etc.\n \n\nThe genome segments are packaged into the core. The RNP (RNA + nucleoprotein, N) is in a helical form with the 3 polymerase polypeptides associated with each segment.\n\n\n© Paul Digard, Dept Pathology, University of Cambridge. \n\nTo view an electron micrograph of negatively-stained influenza virus particles click here.  \n© Russell Kightley Media  \n\nHost Range:\nInfluenza A viruses infect a wide variety of mammals, including man, horses, pigs, ferrets and birds. The main human pathogen, associated with epidemics and pandemics. There are 15 known haemagglutinin (H) serotypes and 9 known neuraminidase (N) serotypes. Pigs and birds are believed to be particularly important reservoirs, generating pools of genetically/antigenically diverse viruses which get transferred back to the human population via close contact between humans and animals. \n\nInfluenza B viruses infect mammals only and cause disease, but generally not as severe as A types. Unlike influenza A viruses, influenza B viruses do not have distinguishable serotypes. \n\nInfluenza C viruses also infect mammals only, but do not cause disease (?). They are genetically and morphologically distinct from A and B types. \nSpecies barrier:\nThe species which different types of influenza viruses are able to infect are determined by different forms of sialic acid present on the virus glycoproteins. In particular, this property depends predominately (but not exclusively) on
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A virus does not fulfill the minimal criteria of life.\nA virus is a chemical construct, as others had said before, it is not capable of reproducing itself.\nA chromosome is a very large collection of chemicals, it may be very similar to a virus. It is part of a living organism, by itself, it is not. \nA virus may 'attack' cells and force them to replicate itself, a chromosome doesn't do that; it doesn't have to. You could think of a chromosome as a virus having found its perfect spot; it no longer has to invade cells...
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Yes, viruses are alive. This is a fact, not an opinion. I am an atheist.\n\nIs a virus alive? \nYes - They reproduce which is a definite form of organization. True, they can not do it on their own, yet all living systems are open systems and depend upon their environment for survival. It is just that the environment a virus requires is another living cell. This is actually true for many symbiotic and parasitic cells. \nA virus is not a living machine . It is only part of a machine, namely the blueprints. The virus only provides the plans, the cell has done the real living work. Outside of its host the virus shows no living qualities.
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Virus contains a nucleic acid core wrapped in a protein coat. This coat is called a capsid. Some viruses contain an envelope, constructed from the host cell membrane. The nucleic acid core may be DNA ( double strand, single strand), or RNA ( single strand, double strand), but never both. The shape of these viruses vary from spherical, cylindrical, bullet-shaped , to amorphous shaped particles. They vary in diameter from 18 to 300 nm. Viruses must infect a living cell. Viruses are obligate intracellular parasites. Some viruses are hardier than others ( hepatitis virus can withstand short periods of boiling; most viruses are destroyed by this).\n \nBacteria are true cells.  Their DNA is singular and circular and found in the nucleoid region of the bacterial cell.  They also contain small double strand ring of DNA called PLASMIDS.\nMost bacteria reproduce by binary fission. There is only one origin of replication. 2 replication forks move in opposite directions. Bacteria can completely divide in 20 minutes under optimal conditions. They are either free-living or parasitic like the virus.  Most bacteria are helpful though some cause some serious diseases.  They mainly help us with decomposition of dead material.
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Non-living\n\nA virus is a submicroscopic obligatory parasitic particle that infects cells in biological organisms. Viruses are "non-living particles" that can only replicate when an organism reproduces the virulent RNA or DNA.
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lysogenic (copies itself in genome of other cells, cell divide...later it enters lytic cell and burst to spread virus\n\nAnswer: Lysogenic cycle
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Quite simple really. viruses can reproduce only inside a living cell.but bacteria can reproduce outside too .\n\nbut it depends what you are  talking about .you'll have to consider the temperature and pH conditions .viruses can survive higher temperatures than bacteria.
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A viruses is a small structure that has a protein coat with a pieces of genetic material.  It invades the cell of its host and uses the hosts DNA to replicate its own genetic material.  Once the cell has replicated the viruses DNA the cell ruptures and the viral DNA is sent throughout the hosts body.  A virus is not technically classified as a living thing.  It is not able to replicate and reproduce with out a host.\nA bacteria is classified as a living thing.  It is a prokaryotic organism with the ability to reproduce using its own genetic material  DNA/ RNA.
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transcription in cells makes RNA copies of DNA.
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Dengue Virus\nThe dengue virus belongs to the Family Flaviviridae. It is an enveloped plus-strand RNA arbovirus. Being an enveloped virus, it has pieces of host cell’s plasma membrane that virion acquires as it emerges from its host cell and with spikes or protruding proteins. As a plus-strand RNA virus, it is translated directly by the host ribosome.  \n\nVirus Life Cycle\nAll viruses undergo the same life cycle. First, it attaches itself to the host cell known as adsorption. Then, the genome enters the host cell in the penetration process. During the uncoating, the virus removes its capsid and envelope. It is followed by the viral synthesis wherein the host cell manufactures viral components. Then maturation process takes place as the components assembles into intact new virions. Lastly, the virus particles leaves infected cell. \n\n\nPathophysiology\nThe transmission cycle of dengue virus by the mosquito Aedes aegypti begins with a dengue-infected person. This person will have virus circulating in the blood—a viremia that lasts for about five days. During the viremic period, an uninfected female Aedes aegypti mosquito bites the person and ingests blood that contains dengue virus. Although there is some evidence of transovarial transmission of dengue virus in Aedes aegypti, usually mosquitoes are only infected by biting a viremic person.\nThen, within the mosquito, the virus replicates during an extrinsic incubation period of eight to twelve days.\nThe mosquito then bites a susceptible person and transmits the virus to him or her, as well as to every other susceptible person the mosquito bites for the rest of its lifetime.\nThe virus then replicates in the second person and produces symptoms. The symptoms begin to appear an average of four to seven days after the mosquito bite—this is the intrinsic incubation period, within humans. While the intrinsic incubation period averages from four to seven days, it can range from three to 14 days.\nThe viremia begins slightly before the onset of symptoms. Symptoms caused by dengue infection may last three to 10 days, with an average of five days, after the onset of symptoms—so the illness persists several days after the viremia has ended.\nTransmission cycle that takes place within the human body.\n1.The virus is inoculated into humans with the mosquito saliva.\n2.The virus localizes and replicates in various target organs, for example, local lymph nodes and the liver.\n3.The virus is then released from these tissues and spreads through the blood to infect white blood cells and other lymphatic tissues.\n4.The virus is then released from these tissues and circulates in the blood.\nTransmission cycle that takes place within the mosquito.\n5.The mosquito ingests blood containing the virus. \n6.The virus replicates in the mosquito midgut, the ovaries, nerve tissue and fat body. It then escapes into the body cavity, and later infects the salivary glands. \n7.The virus replicates in the salivary glands and when the mosquito bites another human, the cycle continues.\nThere are 4 Serotypes of Dengue virus (1,2,3,4 Group B arbovirus). The first attack, neutralizing antibodies are produced principally against this virus type inoculated by the mosquito vector.  Although antigenetically linked to each other, they may only give partial cross-protection, after being infected by any of them. \nThe pathogenesis of hemorrhagic dengue fever is the result of many factors. As the dengue virus attacks the human body, the immune complex or antibody tries to fight off the virus resulting to anaphylactic reactions that produce toxic substances such as histamine, serotonins, and bradyknin which damage the capillary walls. These are responsible for the increase in vascular permeability exhibiting symptoms such as macopopular, rashes, pruritus, edematous extremities, and flushed skin.  Increase in vascular permeability causes extravasation of fluids resulting to fluid shifts especially in the abdomen, p
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Transcription (genetics), the process of copying DNA to RNA by an enzyme called RNA polymerase (RNAP) \nTranscription is the process through which a DNA sequence is enzymatically copied by an RNA polymerase to produce a complementary RNA. Or, in other words, the transfer of genetic information from DNA into RNA. In the case of protein-encoding DNA, transcription is the beginning of the process that ultimately leads to the translation of the genetic code (via the mRNA intermediate) into a functional peptide or protein. Transcription has some proofreading mechanisms, but they are fewer and less effective than the controls for DNA; therefore, transcription has a lower copying fidelity than DNA replication.\n\nLike DNA replication, transcription proceeds in the 5' → 3' direction (ie the old polymer is read in the 3' → 5' direction and the new, complementary fragments are generated in the 5' → 3' direction). Transcription is divided into 3 stages: initiation, elongation and termination.\n\nclick here:http://en.wikipedia.org/wiki/Transcription_%28genetics%29#Prokaryotic_transcription
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In computer security technology, a virus is a self-replicating program that spreads by inserting copies of itself into other executable code or documents. A computer virus behaves in a way similar to a biological virus, which spreads by inserting itself into living cells. Extending the analogy, the insertion of a virus into the program is termed as an infection, and the infected file (or executable code that is not part of a file) is called a host. Viruses are one of the several types of malicious software or malware. In a common parlance, the term virus is often extended to refer to worms, trojan horses and other sorts of malware, however, this can confuse computer users, since viruses in the narrow sense of the word are less common than they used to be, compared to other forms of malware. This confusion can have serious consequences, because it may lead to a focus on preventing one genre of malware over another, potentially leaving computers vulnerable to future damage. However, a basic rule is that computer viruses cannot directly damage hardware, but only software.\n\nWhile viruses can be intentionally destructive (for example, by destroying data), many other viruses are fairly benign or merely annoying. Some viruses have a delayed payload, which is sometimes called a bomb. For example, a virus might display a message on a specific day or wait until it has infected a certain number of hosts. A time bomb occurs during a particular date or time, and a logic bomb occurs when the user of a computer takes an action that triggers the bomb. However, the predominant negative effect of viruses is their uncontrolled self-reproduction, which wastes or overwhelms computer resources.\n\nToday (as of 2006), viruses are somewhat less common than network-borne worms, due to the popularity of the Internet. Anti-virus software, originally designed to protect computers from viruses, has in turn expanded to cover worms and other threats such as spyware.\n\nDefinition:\n===========\nA virus is a type of program that can replicate itself by making (possibly modified) copies of itself. The main criterion for classifying a piece of executable code as a virus is that it spreads itself by means of 'hosts'. A virus can only spread from one computer to another when its host is taken to the uninfected computer, for instance by a user sending it over a network or carrying it on a removable medium. Additionally, viruses can spread to other computers by infecting files on a network file system or a file system that is accessed by another computer. Viruses are sometimes confused with worms. A worm, however, can spread itself to other computers without needing to be transferred as part of a host. Many personal computers are now connected to the Internet and to local-area networks, facilitating their spread. Today's viruses may also take advantage of network services such as the World Wide Web, e-mail, and file sharing systems to spread, blurring the line between viruses and worms.\n\nViruses can infect different types of hosts. The most common targets are executable files that contain application software or parts of the operating system. Viruses have also infected the executable boot sectors of floppy disks, script files of application programs, and documents that can contain macro scripts. Additionally, viruses can infect files in other ways than simply inserting a copy of their code into the code of the host program. For example, a virus can overwrite its host with the virus code, or it can use a trick to ensure that the virus program is executed when the user wants to execute the (unmodified) host program. Viruses have existed for many different operating systems, including MS-DOS, AmigaOS, Mac OS and even Linux; however, the vast majority of viruses affect Microsoft Windows.\n\nA legitimate application program that can copy itself as a side-effect of its normal function (e.g. backup software) is not considered a virus. Some programs that w
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Yes they do and therefore are able to propogate their own kind (also able to show variations by genetic recombination). DNA or RNA both can be used as the building blocks. \n\nThey however try to carry a small baggage when traveling and use the host cell machinary to produce stuff that they need along the way.\n\nA virus is a submicroscopic parasitic particle that infects cells in biological organisms. The study of viruses is virology.\n\nViruses are obligate intracellular parasites that lack the cellular machinery for self-reproduction. Viruses infect eukaryotes and prokaryotes such as bacteria; viruses infecting prokaryotes are also known as bacteriophages or phages. Typically viruses carry a small amount of genetic material, either in the form of DNA or RNA, but not both, surrounded by some form of protective coat consisting of proteins, lipids, glycoproteins or a combination. The viral genome codes for the proteins that constitute this protective coat, as well as for those proteins required for viral reproduction that are not provided by the host cell.\n\nViruses are non-living particles that can only replicate when an organism reproduces the viral RNA or DNA. Viruses are considered non-living by the majority of virologists because they do not meet all the criteria of the generally-accepted definition of life. Among other factors, viruses do not move, metabolize, or decay on their own. However, a comprehensive definition of life is still somewhat elusive since some bacteria (considered living) like rickettsia exhibit both characteristics of living and non-living particles.\n\nBecause viruses are acellular and do not have their own metabolism, they must utilize the machinery and metabolism of the host for the purpose of self-replication. Before a virus has entered a host cell, it is called a virion — a package of viral genetic material. Virions can be passed from host to host either through direct contact or through a vector, or carrier. Inside the organism, the virus can enter a cell in various ways. Bacteriophages—bacterial viruses—attach to the cell wall surface in specific places. Once attached, enzymes make a small hole in the cell wall, and the virus injects its DNA into the cell. Other viruses, such as HIV, enter the host via endocytosis, the process by which cells take in material from the external environment. After entering the cell, the virus's genetic material begins the destructive process of causing the cell to produce new viruses.\n\nThere are three different ways genetic information contained in a viral genome can be reproduced. The form of genetic material contained in the viral capsid, the protein coat that surrounds the nucleic acid, determines the exact replication process.\n\nSome viruses have DNA which is replicated by the host cell along with the host's own DNA.\n\nThere are two different replication processes for viruses containing RNA. In the first process, the viral RNA is directly copied using an enzyme called RNA replicase. This enzyme then uses that RNA copy as a template to make hundreds of duplicates of the original RNA. A second group of RNA-containing viruses, called the retroviruses, uses the enzyme reverse transcriptase to synthesize a complementary strand of DNA so that the virus' genetic information is contained in a molecule of DNA rather than RNA. The viral DNA can then be further replicated using the resources of the host cell.\n\nBacteriophages have two cycles called the lytic cycle and lysogenic cycle. In the lytic cycle the host cell undergoes lysis (the breaking open of the cell to release viral particles), biosynthesis, maturation and finally release. In the lysogenic cycle viral replication does not immediately occur, but replication may take place some time in the future. some viruses e.g. lambda are capable of carrying out both cycles. In the lytic cycle the cell is soon destroyed and the viruses made will have to find new host. However during the lysogenic s
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1) It replicates quickly\n2) it becomes part of your body, killing the virus will kill your immune system in effect\n3) It is a retrovirus and mutates extremely quickly. It is based on RNA and not DNA and does not have a second strand like in DNA viruses so it mutates very very quickly. A cure today will not work in a couple of years. Like the flu virus, the vaccioine changes every year because the flu virus constantly changes\n4) it is hard to determine where exactly the virus is located\n5) It is impossible to completely destroy the virus, only get iut to small amounts
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A bacterium is a microscopic unicellular organism with a simple cell structure, they procreate by fission, that is splitting and sharing DNA.\n\nA virus is a submicroscopic parasite which invades living cells, including bacteria, and hijacks the cell's systems to force the cell to make copies of the virus.
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The answer to your question is (C). \n\nEvery living organism is made up of one or more cells, all cells arise from preexisting cells, the smallest living organisms are single cells, and cells are the functional units of multicellular organisms.\n\n"Virus - a non cellular parasitic particle that consists of a protein coat surrounding a strand of genetic material; multiplies only within a cell of a living organism (the host)."
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Viruses themselves are not alive. Most virologists consider them non-living, as they do not meet all the criteria of the generally accepted definition of life. They are similar to obligate intracellular parasites as they lack the means for self-reproduction outside a host cell, but unlike parasites, viruses are generally not considered to be true living organisms. Among other factors, viruses do not possess a cell membrane or metabolise on their own.\n\ncompter viruses are not alive either.