What are viruses? | ||||
Viruses are non-living microscopic particles that attack healthy cells within living things. They do not have the characteristics of living things and are not able to metabolize food. To metabolize means to change food energy into chemical energy that the body can use. Viruses are not alive, so they do not have a need for food like living oganisms. Viruses do not have an organized cell structure. They are so light that they can float in the air or water, be passed on to other organisims if touched, and fit anywhere. The virus injects its own DNA structure into healthy cells where new virus cells grow. | ||||
How are viruses identified? | ||||
Viruses that are mature have characteristics that help to identify them. RNA(ribonuceic acid) and DNA(dioxiribonucleic acid) structure protein coat that surrounds nucleic acids they invade hosts to reproduce their size | ||||
HIV human immunodeficiency virus infected lymph tissue | Herpes simplex virus invaded vacuole of human cell | |||
Polio virus RNA virus Picornaviridae Family | Influenza A virus Human Infection | |||
How do viruses reproduce? | ||||
Viruses can not reproduce by themselves like bacteria or cells. They must attach themselves to the cell membrane of animals, or cell wall of plants and inject a part of their DNA into the cells of the host organism.. They do this by using a hollow tube structure to puncture the cell wall/membrane and pass its DNA into the cell. New virus cells are incubated inside the invaded cell. Once the virus DNA reproduces itself inside the cell, it uses the natural process of osmosis to leave the cell. These new virus cells attach to other healthy cells and infect them too. | ||||
What do viruses do? | ||||
Viruses invade the cells of both plants and animals. They reproduce inside healthy cells causing diseases that are hard to treat. There are no know anitibiotics or other medicines that are known to kill viruses. | ||||
Viruses like this Plum Pox attack plants and ruin the fruit. It is spread from plant to plant by insects like this green peach aphid |
Sunday, 12 June 2011
viruses
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