The first thing I wanted to do was revise what makes something living alive. The reason for this is that Viruses aren’t generally accepted as being a living thing, but instead of simply teaching that to the children I wanted them to work it out for themselves.
Characteristics of living organisms
– movement as an action by an organism or part of an organism causing a change of position or place
– respiration as the chemical reactions in cells that break down nutrient molecules and release energy for metabolism
– sensitivity as the ability to detect or sense stimuli in the internal or external environment and to make appropriate responses
– growth as a permanent increase in size and dry mass by an increase in cell number or cell size or both
– excretion as removal from organisms of the waste products of metabolism (chemical reactions in cells including respiration), toxic materials, and substances in excess of requirements
– nutrition as taking in of materials for energy, growth and development; plants require light, carbon dioxide, water and ions; animals need organic compounds and ions and usually need water
(This is copied verbatim from an IGCSE syllabus)
Of course, in order to answer the question as to whether a virus is living or not, the children would need to learn a bit more about viruses. They used my computer to find out some facts.
Structure of Viruses
They studied these diagrams of a bacteriophage and retrovirus from BBC’s Bite size GCSE:
As I had done with both bacteria and fungi, I asked them to make their own model of either a virus or a bacteriophage. However, this time I limited them to making it out of Lego, Magnetix or Knex. Each child chose to make a retro virus rather than a bacteriophage. Here are their models:
Replication of Viruses
We then looked at the replication of a virus. BBC bitesize have some very clear diagrams, which I went through with the children, and then we all watched this video:
I wanted them to really understand how cells replicate because it is this replication which causes disease in our bodies. To really drum it home, I had them watch the following video on a cold virus entering the body:
I then asked them to build a cell, in which a virus attacks and then replicates, using their model of the virus made previously. Here they are demonstrating the replication of viruses. All three of them used a hoop as their cell being attacked (it’s not always clear from the photos):
Here is the Lysis cycle as explained by C11:
And here is L11’s:
I thought both girls did a fabulous job and their explanations were very clear. T12 had the Lego option and he spent the whole afternoon making a 3 dimensional model. I somehow missed getting a photo of the actual host cell, but did get a couple of the working machine he made to represent the nucleoid. It was really cleverly done using Lego Technic gears, with a conveyor belt transforming one RNA strand into two. My photos don’t do it justice at all:
Following this brief study of viruses I will be doing two more in-depth studies with them. The first is to look into the flu pandemic of 1918 and the second is to read a ‘living’ book on the 1983 outbreak of Ebola virus in Washington DC, called The Hot Zone.