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Influenza is caused by three related viruses: type A, B, or C. To know more about this, you can download the animation.
Showing posts with label virus. Show all posts
Showing posts with label virus. Show all posts
Influenza is caused by three related viruses: type A, B, or C. To know more about this, you can download the animation.
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RNA has a very similar structure to DNA. However, small differences between the two molecules mean that HIV's replication process is a bit more complicated than that of most other viruses.
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Do you know how to get gene copy? You will see the animation at this file using swf format or flash media.
A gene gun or a biolistic particle delivery system, originally designed for plant transformation, is a device for injecting cells with genetic information. The payload is an elemental particle of a heavy metal coated with plasmid DNA. This technique is often simply referred to as bioballistics or biolistics.
This device is able to transform almost any type of cell, including plants, and is not limited to genetic material of the nucleus: it can also transform organelles, including plastids.
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To know the step of virus infection especially for influenza virus you can see the animation at this file using swf format or flash media.
Infection caused by the presence of a virus in the body. Depending on the virus and the person's state of health, various viruses can infect almost any type of body tissue, from the brain to the skin. Viral infections cannot be treated with antibiotics; in fact, in some cases the use of antibiotics makes the infection worse. The vast majority of human viral infections can be effectively fought by the body's own immune systemInfection caused by the presence of a virus in the body. Depending on the virus and the person's state of health, various viruses can infect almost any type of body tissue, from the brain to the skin. Viral infections cannot be treated with antibiotics; in fact, in some cases the use of antibiotics makes the infection worse. The vast majority of human viral infections can be effectively fought by the body's own immune system
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Virus are intracellular obligate parasites which means that they cannot replicate or express their genes without the help of a living cell. A single virus particle (virion) is in and of itself essentially inert. It lacks needed components that cells have to reproduce. When a virus infects a cell, it marshals the cell's ribosomes, enzymes and much of the cellular machinery to replicate. Unlike what we have seen in cellular replication processes such as mitosis and meiosis, viral replication produces many progeny, that when complete, leave the host cell to infect other cells in the organism.
Viruses may contain double-stranded DNA, double-stranded RNA, single-stranded DNA or single-stranded RNA. The type of genetic material found in a particular virus depends on the nature and function of the specific virus. The exact nature of what happens after a host is infected varies depending on the nature of the virus. The process for double-stranded DNA, single-stranded DNA, double-stranded RNA and single-stranded RNA viral replication will differ. For example, double-stranded DNA viruses typically must enter the host cell's nucleus before they can replicate. Single-stranded RNA viruses however, replicate mainly in the host cell's cytoplasm.
Once a virus infects its host and the viral progeny components are produced by the host's cellular machinery, the assembly of the viral capsid is a non-enzymatic process. It is usually spontaneous. Viruses typically can only infect a limited number of hosts (also known as host range). The "lock and key" mechanism is the most common explanation for this range. Certain proteins on the virus particle must fit certain receptor sites on the particular host's cell surface.
How Viruses Infect Cells
The basic process of viral infection and virus replication occurs in 6 main steps.
1. Adsorption - virus binds to the host cell.
2. Penetration - virus injects its genome into host cell.
3. Viral Genome Replication - viral genome replicates using the host's cellular machinery.
4. Assembly - viral components and enzymes are produced and begin to assemble.
5. Maturation - viral components assemble and viruses fully develop.
6. Release - newly produced viruses are expelled from the host cell.
Viruses may infect any type of cell including animal cells, plant cells and bacterial cells. To view an example of the process of viral infection and virus replication, see Virus Replication: Bacteriophage. You will discover how a bacteriophage, a virus that infects bacteria, replicates after infecting a bacterial cell.
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HIV is the human immunodeficiency virus. It is the virus that can lead to acquired immune deficiency syndrome, or AIDS. CDC estimates that about 56,000 people in the United States contracted HIV in 2006.
There are two types of HIV, HIV-1 and HIV-2. In the United States, unless otherwise noted, the term “HIV” primarily refers to HIV-1.
Both types of HIV damage a person’s body by destroying specific blood cells, called CD4+ T cells, which are crucial to helping the body fight diseases.
Within a few weeks of being infected with HIV, some people develop flu-like symptoms that last for a week or two, but others have no symptoms at all. People living with HIV may appear and feel healthy for several years. However, even if they feel healthy, HIV is still affecting their bodies. All people with HIV should be seen on a regular basis by a health care provider experienced with treating HIV infection. Many people with HIV, including those who feel healthy, can benefit greatly from current medications used to treat HIV infection. These medications can limit or slow down the destruction of the immune system, improve the health of people living with HIV, and may reduce their ability to transmit HIV. Untreated early HIV infection is also associated with many diseases including cardiovascular disease, kidney disease, liver disease, and cancer. Support services are also available to many people with HIV. These services can help people cope with their diagnosis, reduce risk behavior, and find needed services.
AIDS is the late stage of HIV infection, when a person’s immune system is severely damaged and has difficulty fighting diseases and certain cancers. Before the development of certain medications, people with HIV could progress to AIDS in just a few years. Currently, people can live much longer - even decades - with HIV before they develop AIDS. This is because of “highly active” combinations of medications that were introduced in the mid 1990s.
No one should become complacent about HIV and AIDS. While current medications can dramatically improve the health of people living with HIV and slow progression from HIV infection to AIDS, existing treatments need to be taken daily for the rest of a person’s life, need to be carefully monitored, and come with costs and potential side effects. At this time, there is no cure for HIV infection. Despite major advances in diagnosing and treating HIV infection, in 2007, 35,962 cases of AIDS were diagnosed and 14,110 deaths among people living with HIV were reported in the United States.
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Viruses may be defined as acellular organisms whose genomes consist of nucleic acid, and which obligately replicate inside host cells using host metabolic machinery and ribosomes to form a pool of components which assemble into particles called VIRIONS, which serve to protect the genome and to transfer it to other cells.
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