Often referred to as "germs" at a young age, we come to understand bacteria and viruses at a very young age. They are very small organisms and they are helpful as well as harmful. They help us digest foods and in the process make essential vitamins for us. There are only a handful of bacteria that cause us harm and some of them can help breakdown oil after large man made oil spills, helping other walks of life in the balance. There is also a running theory that bacteria produce half of the world’s oxygen. Viruses are many times smaller than bacteria. They are tiny parasites. Naturally they are harmful, but scientists are finding ways to use them to help patients in gene therapy and other health related applications. The volume of bacteria that inhabit the planet is sheerly overwhelming. If you were to collectively count them up, their biomass would far exceed all the plants and animals on Earth. If you were to take a one gram (the weight of a postage stamp) of soil and count the number of bacteria present, you would find close to forty-million bacterial cells. There are just under a half a million viruses that are known to infect mammals, but there are many different types of viruses that reside inside organisms from other kingdoms.
Students will get up close and personal with the anatomy of a virus and be able to identify key structures. We also spend a good bit of time on the anatomy of a bacterial cell, but that is more general. The last selection of the worksheet set examines all the different disease that are caused directly or indirectly in humans by a virus or bacterial infection. These worksheets look at the structure and function of viruses. They also look at structures within bacteria and how they reproduce. We also look at how certain bacteria cause disease.