Virus: All life on Earth has some kind of viruses.
Walter Read discovered the first human virus in 1901. Viruses are everywhere from our surroundings to the very food we eat. We ingest inhale and take in millions of viruses every second. All life on earth has some kind of virus designed specially 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 have 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 multiplication of their genetic materials.
The virus is actually just a piece or strand of genetic information usually DNA or RNA which can be a single or double standard. This is the virus's genome it uses the help of various molecular machines to replicate itself. However, it cannot do this alone it must inject some kind of cell.
Cells are the smallest unit of life they manufacture proteins to replicate DNA and store resources. This makes them perfect hosts for viruses armed with its genetic materials. 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.