Viruses
When is a life form not
a life form?
When it’s a virus!
Viruses are strange things that straddle the
fence between living and non-living. On the
one hand, if they're floating around in the
air or sitting on a doorknob, they're inert.
They're about as alive as a rock. But if they
come into contact with a suitable plant,
animal or bacterial cell, they spring into
action. They infect and take over the cell
like pirates hijacking a ship.
A virus is basically a tiny bundle of
genetic material—either DNA or
RNA—carried in a shell called the
viral coat (or capsid)
Flu virus
What kind of Microbe is it?
Microbes are single-celled organisms
that can perform the basic functions
of life — metabolism, reproduction,
and adaptation.
Except viruses. Viruses can’t
metabolize nutrients, produce and
excrete wastes, move around on their
own, or even reproduce unless they
are inside another organism’s cells.
HIV Virus
They aren’t even cells.
Diagram of Flu virus
When viruses come into contact with
host cells, they trigger the cells to
engulf them, or fuse themselves to
the cell membrane so they can
release their DNA into the cell.
Once inside a host cell,
viruses take over its
machinery to reproduce.
Viruses override the host
cell’s normal functioning
with their own set of
instructions that shut
down production of host
proteins and direct the
cell to produce viral
proteins to make new
virus particles.
Some viruses insert
their genetic
material into the
host cell’s DNA,
where they begin
directing the
copying of their
genes or simply lie
dormant for years or
a lifetime. Either
way, the host cell
does all the actual
work: the viruses
simply provide the
instructions.
Hiv virus
Viruses may be able to infect and
reproduce in more than one kind of animal,
but the same virus can cause different
reactions in different hosts.
For example, flu viruses infect birds, pigs,
and humans. While some types of flu
viruses don’t harm birds, they can
overwhelm and kill humans.
Plant viruses do not infect animals or vice
versa. Viruses that infect bacteria do
nothing to animal or plant cells.
Swine flu virus
Viruses exist for one purpose only: to
reproduce. To do that, they have to
take over the reproductive machinery
of suitable host cells.
Virus or Bacteria?
Because bacteria and viruses cause
many of the diseases we're familiar
with, people often confuse these two
microbes. But viruses are as different
from bacteria as goldfish are from
giraffes.
For one thing, they differ greatly in
size. The biggest viruses are only as
large as the tiniest bacteria.
Another difference is their structure.
Bacteria are complex compared to
viruses.
A virus may or may not have an
outermost spiky layer called the
envelope. All viruses have a protein
coat and a core of genetic material,
either DNA or RNA. And that's it.
Period.
HIV Virus
Viruses are moochers. They contain
only a limited genetic blueprint and
they don't have the necessary
building tools. They have to invade
other cells and hijack their cellular
machinery to reproduce. Viruses
invade by attaching to a cell and
injecting their genes or by being
swallowed up by the cell.
These are T4 bacteriophages (back-tear-eoh-faj-es). They are a kind of virus that
infects bacteria. Here they are landing on
the surface of an E. coli bacterium.
The bacteriophage cuts a hole in the E.
coli's cell wall. It then injects its genetic
material into the bacterium. By taking over
the E. coli's genetic machinery, the viral
genes tell the bacterium to begin making
new virus parts. These parts come together
to make whole new viruses inside the
bacterium.
Eventually so many new viruses are made
that the E. coli bursts open and dies,
releasing all those new viruses to infect
more cells
The way that
viruses spread is
specific to the type
of virus. They can
be spread through
the following
means:
Carrier organisms - mosquitoes, fleas
The air
Direct transfer of body fluids from one person
to another - saliva, sweat, nasal mucus, blood,
semen, vaginal secretions
Surfaces on which body fluids have dried
Virus Video
http://www.npr.org/templates/story/story.php?storyId=114075029
Are viruses and bacteria treatable?
Well………… most bacteria are easily
treatable with an antibiotic which is
prescribed by the doctor.
However………since viruses take over
cells in your body, they are not easily
treated. Usually it is left up to your immune
system to deal with the virus. There are
some new antiviral drugs becoming
available but only for a few viruses.
The best thing is to avoid getting a virus in
the first place.
To reduce the risk of
spreading or contacting
viruses, here are things
you can do:
Cover your mouth or nose when you
sneeze or cough.
Wash your hands frequently, especially
after going to the bathroom or preparing
food.
Avoid contact with the bodily fluids of
others.
These practices are not foolproof, but they
can help you reduce the risk of viral
infection.
Sources
http://www.netdoctor.co.uk/health_adv
ice/facts/virusbacteria.htm
http://www.microbeworld.org/
http://www.nationalgeographic.com/
https://eapbiofield.wikispaces.com/Eri
ka+PR+9+Classification?f=print