Question

5. A slide mount of a fungal specimen is prepared. A slide and coverslip are flame-sterilized. The coverslip is prepared and set on two hardened strips of sterile paraffin on the slide. Molten sterile Sabouraud dextrose agar is cooled to near-solidification point, then inoculated with mold and streamed under the coverslip with a sterile Pasteur pipette. Once the agar has solidified, the slide is placed into a sterile Petri dish and allowed to incubate at room temperature for four days prior to observation. When the slide is pulled, little growth is observed and the medium has become shrunken and cracked under the coverslip. What occurred?

A. The fungus used up all the nutrients in the limited amount of medium, drying it out and then dying off before the slide could be viewed.

B. The medium was too hot, so it quickly evaporated all the moisture out and killed most of the mold sample inoculated into it, leading to limited growth and a dried medium appearance.

C. No moist paper towels were included in the Petri dish during incubation, so the media dried up. With no moisture, the fungus couldn’t grow well.

D. The medium used is an incorrect medium to support fungal growth.

6. What parts of the transformation procedure are done to increase the competence of the bacterial cells?

Check All That Apply

A. Treatment with calcium

B . Brief heat shock

C. Using a microcentrifugeUsing a microcentrifuge

D. Adding LB to the tube

7. A biochemical sugar fermentation test that can differentiate N. gonorrhoeae from both N. flavescens and M. nonliquefaciens is the ability to ferment

• tryptophan

• lactose

• glucose

• sucrose

Answer 1

5. Mycelial and fungal spore arrangement is studied using slide culture technique where we have to maintain favorable conditions like nutrient, pH, temperature and available water (aw, moisture content). Fungi requires moisture conditions during growth.It can be achieved by using sterile filter paper/paper towel wetted with sterile water or glycerol.In this case after 4 days of incubation, we are expecting complete mycelial growth with spore.But here less growth and crack agar indicates that proper moisture condition is not maintained.

Hence answer is C.

6.Transformation is the process by which competent bacteria take up foreign material. Competent cells are prepared by making its cell and membrane permeable to DNA either by brief heat shock treatment or using calcium chloride/phosphate.So the answer is A and B.

7. Neisseria gonorrhoeae ferment glucose with acid production.which is not in the case of N.flavescens which could not ferment carbohydrate.Moraxella nonliquefaciens could not ferment glucose.