Kind: captions
Language: en
all might seem outwardly peaceful but
right now tiny battles are raging inside
of you the battles are being fought for
control of the molecular Machinery that
runs your cells and keeps them and you
alive who are the attackers they are
minuscule yet deadly viruses if you've
ever had chickenpox the flu or the
common cold your cells have fought and
defeated viruses your cells have
factories with the power to create
molecular
machines viruses need to hijack those
factories to copy themselves because
they do not have factories of their
own each virus is like a little tank
that can blast a hole in the outer cell
wall and send its forces
in these Intruders change the blueprints
in the Factory's headquarters so the
factory starts producing more viral
tanks it doesn't stop until it builds so
many tanks that the cell bursts right
open
this is what a virus attack might look
like if you were the size of a cell most
viruses are little more than genetic
information DNA or RNA inside a protein
shell they bind to a cell and inject
their genetic code
inside the invaded cell treats this code
as its own and starts making virus
protein components to build new
viruses when enough viruses have been
assembled they burst through the cell
membrane and the whole process starts
again fortunately your cells have
evolved their own defenses when you get
sick with the flu at first the viruses
win out but then your immune system
learns to recognize and destroy the
Invaders one immune response which was
only recently discovered in plants and
some animals is called RNA interference
or
RI cells make a protein called dicer
it's always on the look out for double
stranded RNA which is used by many
viruses but rarely by cells when dicer
finds this RNA it dices it
up dicer doesn't stop all the viral RNA
from getting through but it doesn't need
to because RNA has a great trick up its
sleeve it uses those chopped up pieces
of RNA As Weapons against the
virus those chopped up rnas are shreds
of the virus's blueprint for copying
itself now when that virus tries to
hijack the cell's Factory RNA molecules
are ready they check all the protein
assembly instructions against the
chopped up virus RNA Snippets anything
that matches is something that the virus
is trying to make so the cell slices it
up before it makes a protein and just
like that the cell defeats the virus RNA
is not only a great defensive weapon but
also a powerful tool for biological
research scientists can use the same
basic mechanism of RNA interference to
turn off one gene at a time and study
the effect on the cell and the organism
for example turning off one gene made
drain all of the pigment out of a purple
flower another might prevent a plant
from producing a toxic chemical making
it safe to eat scientists have not yet
determined whether human cells naturally
fight viruses with RNA but it is
possible that one day we will be able to
use RNA to deactivate cancer-causing
genes and genetic disorders meanwhile
viruses and cells will continue evolving
ingenious weapons to try and gain the
upper hand as the great virus Wars rage
on