You treat the following five cultures of bacteria with penic…

You treat the following five cultures of bacteria with penicillin: Bacillus subtilis, E. coli, Mycobacterium tuberculosis, Mycoplasma genitalium, and Staphylococcus aureus. Assume all are “wild type” and have not acquired specific resistance to penicillin (i.e., resistance has not been selected for in any of these strains). Which of these is most likely to survive your treatment with the least harm, i.e., is the most intrinsically resistant to this treatment of penicillin?

You have a culture of E. coli growing in log phase in a chem…

You have a culture of E. coli growing in log phase in a chemically defined medium containing glucose as the sole source of carbon. You take a small sample of cells and transfer them to another chemically defined medium that contains lactose as the sole source of carbon. In this new environment, you would predict these cells would first enter what phase of growth?

Microbiologists estimate we have grown and studied less than…

Microbiologists estimate we have grown and studied less than 1% of all prokaryotes present on Earth. We have been estimating this same number for at least the past two decades. What is the most likely explanation for why this number has stayed relatively constant at 1%?

You have two species of bacteria with the same growth rate a…

You have two species of bacteria with the same growth rate and metabolism. Species A is capable of chemotaxis in response to the carbon source you provide in the growth medium, whereas species B is non-motile and will generally sink to the bottom of the tube. You inoculate identical numbers of cells of each species into each of two test tubes (i.e., species A into test tube 1, and species B into test tube 2) and use a spectrophotometer to measure their growth, being careful not to shake or mix the tubes when taking your measurements. Assume nutrients diffuse slowly within the media. Which species should use up nutrients faster and reach stationary phase first?