Microbiology Lab 26 Quiz Study Guide

Microbiology Lab Quiz Study Guide PART 1: Questions you got wrong 1. Give the magnification of your microscope’s objective lenses and the total magnification when combined with the ocular lens. a. 2x = 20x b. 4x = 40x c. 10x = 100x d. 100x = 100x 2. What the items that you can use to clean your microscope lenses? a. Lens paper 3. When focusing a slide, you should start under what objective? a. 10x 4. What is the red pigment called in an NA slant? a. Prodigiosin 5. The microscopes we use are parfocal. What does this mean? a. Using the same focus for the objective 6. What is the difference between resolution and focus? a. Focus is clarity and resolution is the minimum distance between two organism 7. Most bacteria that are capable of motion do so by the use of what special structure? a. flagellum 8. Why is agar medium slanted in the test tube? a. Increasing culture of growth 9. Describe the shape of the bacteria a. Balls = coccus b. Rod with tails all over = Spiral c. Curvy rod with tails on one end = spirallum 10. What is the difference between selective media and differential media? a. Selective media is the favor of growth appearances or disfavor of growth appearances b. Differential media is the result of different growth appearances by different groups of bacteria c. All selective media are differential media, not vice vera 11. What is beta hemolytic and alpha hemolytic a. Beta hemolytic is the complete or nearly complete breakdown of RBC, and it has clear or whitish zone around it b. Alpha hemolytic is a partial damage of RBC, and it has brown or green zone around it due to the leakage of potassium 12. Describe how cells are diluted to allow the formation of colonies when working with a streak plate versus when working with a pour plate. a. Streak plate allows the separation of colonies b. In pour plate, we are looking for pure colonies 13. Which of the following is not a dye or rinse used during a step of the gram staining process? a. Marigold green b. Iodine c. Safranin red d. 95% ethyl alcohol e. Crystal violet 14. What is the physiological difference between a Gram negative and a gram positive bacteria as explained in the manuel? a. Gram negative is pink; thin cell wall with multiple layers b. Gram positive is purple; thick cell wall 15. True or false: A growth curve measured from a unknown, pure cell stock can be used to identify what species is present in the stock. 16. True or False: Mannitol salt agar is both selective and differential media. a. Why? All selective media are differential media. 17. What is the diameter of this bacteria given that 5 ocular units are equal to 143 um? You may leave answer as a fraction. a. 143/5 18. What is zone of inhibition? a. It is the area where no growth happens b. Resistance 19. Name any bacteria in proper scientific notation and label if its gram positive or negative. a. Escherichia coli, gram – rods, pink 20. In exercise 10 of the food lab, what main ingredient decreases bacterial count? a. Why? Mayonnaise due to its acidity and lyses 21. In the citrate utilization test, a positive test results in the bromothymol blue (a pH sensor that changes from green to blue when the pH increase above 7.6) being blue. How can this be the case, considering that there are no basic metabolic byproducts of citrate being metabolized. a. It is being metabolized by acid 22. You read a TSIA slant as red/yellow. True or False: this information indicates that the species on your slant only metabolizes a single carbohydrate. 23. What is the test that is not part of the IMViC test? a. Methyl red b. Iodine reading (simple stain reading) c. Citrate utilization d. Indole test e. Voges-Proskauer test 24. What is the advantage of a bacteria that produces a water insoluble pigment when you are observing its growth on agar? a. It doesn’t kill the bacteria 25. Fill out the table: pH sensor name Phenol Red (MSA) Methyl Red Bromothymol Blue Color when in Acid Yellow Red Green Color when in Base Dark red Yellow or yellowish orange Blue 26. Write this organism’s name in the proper scientific format: bAciLLUS cerEUS Var. MYcOidES a. Bacillus cereus var. mycoides