Microbiology Lab Test, Micro lab 1 Questions with Correct Answers Graded A+

Microbiology Lab Test, Micro lab 1 Questions with Correct Answers Graded A+ Why are thick or dense smears less likely to provide a good smear preparation for microscopic evaluation? It will diminish the amount o flight that can pass through making it difficult to see under the microscope. Why is it essential that smears be air-dried? Why can't they be gently heated over the flame to speed up the drying process? 1. Overheat will denature and rupture the cell wall. 2. excess water on the slides will boil during fixation Why should you be careful not to overheat the smear during the heat-fixing process? Overheating will distort the morphology through plasmolysis of the cell wall Why do you think the presence of grease or dirt on a glass slide will result in a poor smear preparations? 1. Bacteria will attach to the grease or dirt and wash away when staining. 2. It can also diminish the microscopic light making it hard to see the cells. Why are basic dyes more effective for bacterial staining than acidic dyes? Basic stains with a positively charge chromogen are preferred because bacterial nucleic acid and certain cell wall components carry a negative charge that strongly attract and binds to the cationic chromogen.