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11. What type of staining is most useful for studying the morphology of bacteria

ID: 217311 • Letter: 1

Question

11. What type of staining is most useful for studying the morphology of bacterial cells and characterizing some of the external structures such as the capsule? a. staining b. staining c. Acid fast staining d. Negative staining 12. Examples of basic dyes used in the Microbiology lab are a. Methylene blue b. Crystal violet c. Safranin Two methods available for d. All of the above 13. Microbiologists for obtaining pure cultures are the pour plate method and the a. Dorner method b. Gram stain method. c. Streak plate d. Inoculating method 14. A medium such as EMB (Eosin methylene blue) that allows certain bacteria to grow but inhibits others from growing is an example of a a. Complex b. Defined medium c. Selective d. minimal 15. To destroy all forms of life including endospores, all media is sterilized using a. Dry heat b. Radiation exposure for 30 minutes c. A pressure cooker d. Exposure for 15-30 minutes to steam under pressure (15psi) 16. An organism such as ?. E. coli b. S. aureus is classified as gram negative. d.Both a and e are correct e. P. vulgaris 17. Plates should be inverted during incubation to avoid a. Contamination b. Transformation of bacterial cells d. All of the above c. The buildup of condensation on the medium 18. The purpose of heat fixing a smear is to a. Adhere the cells to the slide b. Preserve their structural integrity c. Kill the cells d. Both a and b are correct 19. Gram staining is an example of a. Acid fast staining b. Acid staining c. Differential staining d. All of the above e following statement are true regarding gram positive bacteria ell wall has a thick peptidoglycan layer h. Cell wall has a thin layer of peptidoglycan layer 20. Which of th r is d. Alil of the above are true of gram positive bacteria 21. After ethanol treatment, an organism such as E. coli can be visualized a. Only by counterstaining with crystal violet c. Only by the addition of lodine b. Only by counterstaining with safranind. All of the above 22. In Gram staining the primary stain used is Methylene blue b. Crystal violetc. Safranin d. Malachite green

Explanation / Answer

11- c acid fast staining

12- all of above

13 streak plate method

14- selective media

15- exposure to steam till 15-20 min under pressure

16 a and c

Note - e coli and p vulgaris are gram negative while s aureus is gram positive bacteria.