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
Photographic
Citations:
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