Human Body - Week 20 - Viruses and Bacteria

 Week 20 - We learned about the differences between viruses and bacteria and made models of both.

Although viruses and bacteria can both make us sick they are very different. Pathogens or germs are names we use to refer to both bad viruses and bacteria.

Bacteria are living cells that come in three shapes; rods, spirals, and spheres. The cells have DNA, but lack a nucleus. They can reproduce rapidly when in the right environment. Most are harmless, some are good and a few are dangerous to humans. Good bacteria such as yeast give texture to our bread products and break down food in our digestive systems. Macrophage cells in our immune systems work to destroy bad bacteria, and antibiotics can help when bacteria become too numerous.

Viruses are much smaller than bacteria and reproduce by taking over a host cell. They cannot live without a host and are destroyed by the T-cells found in our immune systems. H and N surface proteins protrude from viruses and are the way scientists differentiate between them.

We read The Way We Work by David Macaulay to get a better understanding of the differences between viruses and bacteria and then took a few notes.

Bacteria come in three shapes, so each child chose a shape of bacteria to create and I created a virus. The kids were able to choose from any of the crafting materials in the house to create their bacteria.

My son chose to create a rod shaped bacteria by sewing two ovals together and stuffing them.

The spiral bacteria was created by coiling a pipe cleaner and the spherical bacteria was created by gluing a few pom-poms together.

I created the virus by needle felting a sphere and adding thumb tacks to represent the N proteins which cut the viruses loose from host cells and pins to represent the H proteins which hold the viruses to host cells.

More Human Body science projects are available on our Science Page.


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