21. These are Citrate media, A and B.  Describe the reactions in tubes A (left) and tube B (right).  (3pts).   What indicator is responsible for the color in tube B (right)? (2pts)                                      

30. Organisms in the family of Enterobacteriaceae can be differentiated using a battery of tests called IMViC.  What does does IMViC stand for?

23.  What is the difference between a wet mount and Simple stain?

5. This is MacConkey agar plate divided into 2 sections.  Section A is streaked with             organism A and section B with organism B. Describe the reactions in sections A and             B and give a reason for the reactions (4pts).                         A————————————————————————————————             B————————————————————————————————-   B.        What type of media is MacConkey Agar? (2pts).               —————————————————————————————————

22.  Name 2 environmental factors that can influence the growth pattern of microorganisms. 

20.  These are SIM media.  Describe the reactions in tubes A, B, C, D, E

25. Name and describe 3types of Flagella

27.  Suppose your professor handed you a test tube with 2.0 mL of an E. coli broth culture and told you to make a 10-1 dilution of the entire culture.  Explain how you would do this.  Show your calculations.

28.  You plated 0.1 mL of a sample diluted by a factor of 10-5 and after incubation you counted 50 colonies.  The concentration of bacteria in the original culture is:  NOTE: 10-5 is 10 to the negative 5 and 10+5 is 10 to the power of positive 5.

18. Give two reasons for the differential staining between gram + and Gram – organisms (2pts).