Environmental Effects on Microbes

1. Describe the effect of higher and lower than optimal temperatures on bacterial enzymes and membrane lipids

2. Describe the effect of higher than optimal pH on molecule solubility and enzyme activity. Which pH do most bacteria prefer?

3. Describe the effect of a hypertonic environment on bacteria. 

i. Which pathogenic bacterial species is halotolerant?

ii. Why does it thrive on skin?

4. In the pH experiment, predict which organisms grow best in acid and in alkaline media.  (Hint: Saccharomyces is a yeast, and Sporosarcinaproduces ammonia

5. Describe the reason for the control quadrant in the diagram in Exercise 29.

6. Define lysozyme, its origin, and its effect on the peptidoglycan wall.  Which bacteria are most sensitive?  Why?

7. Define and distinguish between antibiotics and antimicrobials.

8. Name three factors that influence the zone of inhibition.

9. Name the two different external structures of Gram positive and Gram negative organisms that make each more resistant to antibiotics.

10. Distinguish between disinfectant, antiseptic, sanitizer, sterilant, bacteriostatic, and bacteriocidal.

11. Name two common antiseptics and name two household disinfectants.

12. Describe the use and effectiveness of alcohol. Name one disadvantage to using alcohol as an antiseptic.