The biggest difference between viruses and bacteria is that viruses must have a living host – like a plant, animal or human – to multiply, while most bacteria can grow on non-living surfaces. Bacteria are intracellular organisms (they live in-between cells), whereas viruses are intracellular organisms (they live inside the cell).
Antibiotics can kill bacteria but not viruses. An example of a disease caused by bacteria is strep throat and an example of a viral infection is the flu.
Bacteria are single-celled micro-organisms and carry all the necessary material needed for their growth and reproduction. Bacteria usually reproduce asexually – meaning that each cell divides into new, genetically identical cells, with each cell functioning as an independent unit. This process is known as binary fission and each cell will continue to multiply until the growth condition diminishes. The population growth curve for bacteria is an exponential curve, whereby with each generation the number of bacteria doubles and under ideal circumstances a single E.coli bacterium can grow to more than one million bacteria in as little as three and a half hours. For one Mycobacterium tuberculosis to generate the same number, again under ideal circumstances, may take as long as ten days.
Viruses are sub-microscopic particles and are the smallest and simplest life form known, they are 10 to 100 times smaller than bacteria. Opinions differ on whether viruses are actually a form of life, or organic structures that interact with living organisms, without a cellular structure or their own metabolism, they need a host cell to reproduce. Once inside a cell they reproduce millions of copies the cell will burst and the newly created viruses are in search of another living organism to infiltrate. Viruses may cause systemic infections. Vaccines and anti-viral medication help to slow the reproduction of the virus but it is difficult to eliminate. All viruses are harmful. Read more…