COLLEGE OF STATEN ISLAND G MALLOY BIO 351 QUIZ I Placing a b

COLLEGE OF STATEN ISLAND G MALLOY BIO 351 QUIZ I. Placing a bacteri in a hypotonie solution will result in cell lysis. TRUE FALSE um 2. Staph aureus is more resistant to the effects of osmotic pressure than Ercoli FALSE 3, Based on optimum temperature requirements, E. coli can be classified as a 4. Indicate the direction of the now of water when a bacterial cell is placed in the solution into the cell out of the cell 5. Hypertonic 6. hypertonic 7. At what temperature do we see maximum production of pigment by Serratia marcescens 8. Give an example of how creating a hypertonic environment can be used as a means of controlling microbial growth. 9. Explain why optimum growth and maximum pigment production of Seratia marcescens occurred at different temperatures 10. Which osmotic environment would be most detrimental to bacterial growth? a. Hypotonic b. hypertonic c. isotonic

Solution

1. True

2. True. They are more salt tolerant

3. Mesophile - optimum temperature is 37C

4. Isotonic - both into and out of the cell

5. Hypotonic - into the cell

6. Hypertonic - out of the cell

7. Temperature below 30C

8. When cells are placed in Hypertonic medium, water from cell is moved out which shrinks the cell. Salt and sugar solutions are used for this mechanism in food preservation.