Since man first tried to classify living things and describe their relatedness, physical attributes have always been the most important quality used for comparison. It is easy to tell an oak tree from a stalk of corn because of the obvious physical differences. However, physical comparison is of much less value when identifying bacteria. Under the microscope, E. coli and Salmonella typhi and hundreds of other species of bacteria are indistinguishable. Scientists needed additional tools to provide identities for various pathogens and harmless species. Exploration of metabolic abilities and limitations of similiar-appearing bacteria has provided valuable information to allow determination of identity.
Bacteria are incredibly versatile in their metabolic capabilities. Some can make DNA and proteins from glucose, ammonia, and a few minerals. Others have very exacting requirements for complex molecules and cannot grow without them. Using knowledge of such differences is what allows identification.
Another thing to remember is that any differences in the metabolism of bacteria from that in humans provides medicine with a potential target for an antibiotic strategy. For instance, if a particular enzyme reaction that is vital for survival is common in bacteria but absent from humans, a chemical disrupting that reaction would kill bacteria without harming the patient. Such differences in prokaryotic and eukaryotic physiology means we have opportunities to selective kill pathogens.
In this collection of activities, some basic information on microbial physiology (microbial metabolism) will be obtained using the VUMIE 2012 simulation and MDM exercises. Then, we will go on a scavenger hunt to see how an understanding of microbial metabolism is important to food production and preservation. We will conduct some simple experiments on microbial metabolism via kitchen microbiology with bread yeast. And, for those schools choosing to require home microscopy we will look at the microbes growing in those experiments.