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What is a virus? How do viruses work?

Walter Reed discovered the first human

virus in 1901 but what is a virus

viruses are everywhere from our

surroundings to the very food we eat

we ingest inhale and take in millions of

viruses every second

pretty much all life on Earth has some

kind of virus designed specifically to

infect it including bacteria and even

other viruses viruses are tiny very tiny

you cannot visibly see them in fact they

are so small that if bacteria had eyes

even they wouldn't be able to see all of

them most scientists accept that viruses

are not living but a complex collection

of organic matter that is able to

self-replicate

they mostly consist of a shell made of

protein which inside contains either DNA

or RNA with enzymes for replication and

manipulation of their genetic materials

are you still with me

good let's look more closely a virus is

actually just a piece or strand of

genetic information usually DNA or RNA

which can be single or double stranded

this is the viruses genome it uses this

with the help of various molecular

machines to replicate itself however it

cannot do this alone it must infect some

kind of cell cells are the smallest unit

of life they manufacture proteins

replicate DNA and store resources this

makes them perfect hosts for viruses

armed with its genetic material viruses

are able to infect healthy cells and

convert them into mindless virus

producing robots

the virus uses this outer protein coat

covered in small molecular receptors to

bind and join to the membrane of a cell

this is essential as it is what

determines which cells a virus is able

to infect once joined the virus uses

several complicated biological pathways

in order to force the cell to either

accept its genetic material or take in

the entire virus itself once in the cell

the virus will then begin to use its

molecular Arsenal to hijack the cell's

protein manufacturing systems and DNA

replication mechanism after the virus

has integrated itself into the cells own

DNA the cell will then replicate its DNA

and use it to manufacture proteins

without the cell even knowing it

produces viral protein shells filling

them with virus DNA effectively making

copies of the virus and assembling them

the virus making machine begins to take

over more and more of the cells protein

manufacturing ribosomes churning out

thousands of new viruses which quickly

fill the cell these viruses then cause

tension within the cell and by several

different means bursts from the cell

with the intention of infecting new

hosts for the same purpose

seems like relentless biological

vandalism to me viruses are not all bad

though some are being used to help

strengthen disease resistance in crops

whilst others such as HIV are being used

in curing certain types of cancers but

what is the most remarkable of all is

that many scientists believe some

viruses that infected bacteria billions

of years ago helped form the first cell

nucleus if this is true then all complex

cellular life on Earth descended from a

single virus and his rubbish attempt at

trying to infect a bacterium now that is

remarkable

you