Definition of virus in biology. Biology for Kids: Viruses 2018-07-31

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What is the definition of virus? (In biology)

definition of virus in biology

Until this time, the poliovirus could be grown only in the brains of chimpanzees or the spinal cords of monkeys. That's why sometimes people a fever as a side effect of a vaccine. Viruses, Bacteria and Life Itself While we suffer from all sorts of viral infections, ranging from the flu, to the common cold and stomach flu, we aren't the only ones affected by viruses. Viruses are very small particles that can infect animals and plants and make them sick. This is known as the lytic cycle. Our mission is to provide an online platform to help students to share notes in Biology. Viruses are so small that you usually need an electron microscope, as opposed to a light microscope you may find in your school lab, to even see one! From a selfish standpoint, viruses exist purely to infect unwilling hosts and to utilize the host's machinery for reproduction, so that their babies can infect other hosts.

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Biology for Kids: Viruses

definition of virus in biology

But they exhibit certain properties, for example, the ability to reproduce their kind, which are normally associated with life. Influenza C virions are structurally distinct from those of the A and B viruses; on infected cell surfaces, they can form long cordlike structures on the order of 500 μm. In other words, viruses are highly specific to their hosts. A ~ is a small infectious agent that replicates only inside the living cells of other organisms. The virion capsid has three functions: 1 to protect the viral nucleic acid from digestion by certain enzymes , 2 to furnish sites on its surface that recognize and attach adsorb the virion to on the surface of the host cell, and, in some viruses, 3 to provide proteins that form part of a specialized component that enables the virion to penetrate through the cell surface membrane or, in special cases, to inject the infectious nucleic acid into the interior of the host cell. A Viral History Therefore, it's amazing, given the limited technology of the time, that on February 12, 1892, in St.

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* Virus (Biology)

definition of virus in biology

A ~ reproduces by ing its genome into the cells of other life-forms. Viruses can also be passed on by insect bites, animals, or through bad food. Kindly provided by Megan L. The ~ then uses the mechanisms of a cell it infects to replicate itself. To put it into a better perspective for you, an average virus is about eight times bigger than a ribosome, whereas the average bacteria is about 30 times bigger than your average virus.

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THE BIOLOGY OF INFLUENZA VIRUSES

definition of virus in biology

Lytic Cycle C is correct. In a few cases, seeds of plants are known to carry virus particles and thus to transmit the virus from one generation to the next. They are the smallest living organisms. Or are they the descendent of some com­plex living organisms which have lost their capacity for an inde­pendent existence during the passage of time? In most cases our body's immune system fights off the virus. Everything you always wanted to know. Evolution See Brief definitions Evolutionist.

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Virology

definition of virus in biology

Typically, the lysogenic cycle is seen much more in prokaryotic viruses, probably because prokaryotes are constantly dividing, where the cells in a may exist without ever dividing, such as some nerve cells. The proton Motive Force cannot be performed by these particles by the simple reason that they do not possess s, or. Conditional Mutations: Mutations occurring only under certain specific conditions. In some cases, the viral capsid may also be surrounded by a viral envelope, which is a lipid bilayer derived from the host cell and one that increases the infectivity of a virus. Viral Structure After many years of study by many brilliant individuals around the world, we have come to understand some of the basic nature of the viruses that threaten us, plants and even bacteria. In fact, viruses should not even be considered organisms, in the strictest sense, because they are not free-living; i. Many people say they are non-living because they cannot reproduce without the aid of a host.

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biology

definition of virus in biology

© Massachusetts Institute of Technology This article discusses the fundamental nature of viruses: what they are, how they cause infection, and how they may ultimately cause disease or bring about the death of their host cells. New varieties are constantly being described. For more-detailed treatment of specific viral diseases, see. Viruses range in size from about 17 to 450 millimicron. Basically, the diameters of different viruses fall somewhere in between that of a bacteria on the high end, and that of a ribosome on the low end, which is essentially a range of about 20-300 nanometers in diameter. Viruses that infect bacteria are called bacteriophages.

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Virology

definition of virus in biology

. ~ A very small organism that can multiply only within living cells of other organisms and is capable of producing disease symptoms in some plants and animals. One example of a vaccine is the flu shot. The Potato mosaic and cattle pox are larger in size. General features Definition Viruses occupy a special taxonomic position: they are not plants, animals, or bacteria single-cell organisms without defined nuclei , and they are generally placed in their own kingdom.

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virus

definition of virus in biology

The true nature of the viruses still remains a debatable issue. A or sequence that is derived from, and therefore partially to a normal gene, but is not transcribed and does not create a al protein. One of the most common is influenza which causes people to get the flu. This is still open to debate, however. Since these processes are already happening in the bacteria, the lysogenic cycle can be thought of as the virus hitching a ride on the efforts already being spent by the bacteria. Viruses can also infect plants. The particular structure of the influenza virus genome and function of its viral proteins enable antigenic drift and antigenic shift.

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