In biology, a virus (from the Latin virus, 'toxin' or 'poison') is a microscopic infectious entity that can only multiply insidethe cells of other organisms. Viruses infect all types of organisms, from plants to animals and bacteria and archaea. Viruses are too small to be seen with the aid of a microscope, so they are saidto be submicroscopic. The virus is found in almost all ecosystems on Earth and are the type most abundant biological entity
Not all viruses cause disease, as many viruses reproduce without causingany damage to the infected organism. Some viruses like HIV can cause permanent or chronic infections as the virus continues to replicate in the body, evading the host defense mechanisms
Antibioticshave no effect on viruses, but antiviral drugs have been developed to treat infections potentially mortals
Bacteria are unicellular microorganisms that have a size of some micrometerslong (between 0.5 and 5 um usually) and different shapes including spheres, rods and propellers.
bacteria are the most abundant organisms on the planet. Are ubiquitous, being found in any habitat onearth, growing in soil, acidic hot springs in radioactive waste, one in the depths of the sea and the earth's crust. Some bacteria can even survive in extreme conditions of outer space.It is estimatedthat some 40 million bacterial cells in a gram of soil and a million bacterial cells in a milliliter of fresh water.
Antibiotics are effective against bacteria and inhibiting the formation of the cellwall or stop other processes of its life cycle. They are also used extensively in agriculture and livestock in the absence of disease, which causes it to be widespread resistance of bacteria toantibiotics
industry, bacteria are important in processes such as wastewater treatment, production of cheese, yogurt, butter, vinegar, etc.. and in the manufacture of drugs and other chemicals