There are 5 TSIA media A-E beginning from the left. Describe the reactions in tubes B, C, D, E only.

Calculate the GI50 value from the graph showing different concentrations of N3P. Show full working. Explain if cytotoxicity is caused by test agent.

There are 10 mL of a culture of a bacteria at 104 cells/mL into 990 mL of the same broth at the same temperature (37° C) It is 8 p.m. the night before your lab which starts at 11 a.m. Doubling time for this species is 40 minutes. Will the culture reach Stationary Phase before your lab? Set up the equation correctly, solve for t, and tell me what time the culture will reach Stationary Phase.   t /g = (Log Nt – Log N0) /0.301

What conditions are necessary to destroy endospores? In what device are these conditions achieved?

Helicobacter pylori, a bacterium that causes stomach ulcers, can grow in medium with a pH above 5.  It can survive but not grow in pH 2 medium as long as the medium contains Urea.  You inoculate a pH 2 broth with 1,000,000 H. pylori and for 8 hours the organism did not grow.  The next morning however, the medium has become quite turbid, suggesting that the organism has grown.  Explain how this could happen. What phylum and class does this organism belong?

on the thioglycolate tube where would you expect to see growth of facultative anaerobes

Catalase Yeast Test Questions: 1. Why is it important to graph volumes that did not include the initial volume? 2.  How might the temperature of the yeast mixture affect a reaction? 3. What effect would increasing the amount of yeast have on a reaction?