EVERYDAY SCIENCE

Detailed explanation-1: -Viruses are even smaller than bacteria. They aren’t even a full cell. They are simply genetic material (DNA or RNA) packaged inside of a protein coating. They need to use another cell’s structures to reproduce.

Detailed explanation-2: -Bacteria are giants when compared to viruses. The smallest bacteria are about 0.4 micron (one millionth of a meter) in diameter while viruses range in size from 0.02 to 0.25 micron.

Detailed explanation-3: -There are things out there even smaller than viruses. The two that scientists have discovered are called prions and viroids. A prion is (as far as we know) just a protein. Prions are proteins that can invade cells and somehow direct their own duplication, making more of the isolated proteins.

Detailed explanation-4: -Viruses are the smallest of all the microbes. They are said to be so small that 500 million rhinoviruses (which cause the common cold) could fit on to the head of a pin. They are unique because they are only alive and able to multiply inside the cells of other living things.

Detailed explanation-5: -The mimivirus that infects the amoeba Acanthamoeba polyphaga made newspaper headlines because its genome is much larger than those of the smallest bacteria (around 160 kb for Carsonella ruddii) and codes for more than 900 proteins (114 being vehiculated by the virion).