What is the major difference between bacteria/viruses and parasites?

Bacteria and viruses can survive on their own although by feeding on stuff like food which is outside the body while parasite take the body they live in as their house, feeding on the food inside that the victim swallows and maybe excrete wastes too.

What is the major difference between bacteria/viruses and parasites?
Bacteria/viruses are more minute and tiny, and they cannot be seen by the naked human eye. Parasites tend to be larger specimens (ex. some are worms that are live in the human's stomach, and etc.). They can be a type of insect or animal that lives in another specimen.
Reply:Lets see if I can remember my biology classes?


Viruses are nothing but DNA bunched up together inside a shell. They don't really have a cell that's why they have to attack cells to reproduce.


Bacteria have cells. They don't really cause a problem most of the time as long as their populations are kept in check by the good guy bugs. We have certain bacteria normally living on our skin, in our mouths and guts and they usually never bother us.


Some parasites are full fledged critters and are multicelular. They are critters that live on other critters and probably don't do them (the host) any good but not all of them kill the host. Some do. There are certain wasps who's larva are parasites on caterpillars. The wasp lay's her eggs on (or is it in) the caterpillar and when they hatch the eat the caterpillar...alive. (shiver)


Other parasites are the common flea and hair lice.


But there are some, I think, that are single cell critters, like the amoeba's. Parasites can do from little or no harm to eventual death. (remember that poor caterpillar!)


Does that help?
Reply:Bacteria are cells without a nucleus. Bacteria can grow on a culture in a petri dish. They are unicellular.





Viruses are non-cells. They are nucleic acids with a protein coating and do not have organelles or a plasma membrane or cell wall. Viruses cannot grow outside a living host cell.





Parasites are multi-cellular creatures. They can live for a while outside a host organism, but they do require a host organism for long-term survival and reproduction.