Question

letters C. & D.

35 EXERCISE 3: MICRORES IN THE ENVIRONMENT remove the stop- fingers of your oth- the flask by passing ames (FIGURE 2a). the flask at an an- first dish with the Buickly and neatly into the dish until a depth of approx 2b). Keep the flask dish cover, move he agar is poured. gently swirl the empty spaces: do he dish covers. eave the Petri plate + 15 minutes until (a) Remove the stopper, and flame the mouth of theflask discard area. ronment: C. The purpose is to d your body. Use ome suggestions: (b) Remove the cover from one dish and pour nutrient agar into the dish bottom. FIGURE 32 Petri plate pouring. from an envi- ce, such as the inch, by wetting sterile water. ironmental swabbing the ar. Why is the ned in sterile on, discard ontainer of mne nutrient the air for 30 b. Inoculate two plates from the environment and two plates from your body. Inoculate one nu- trient broth tube using a swab. Wet a swab in sterile water and swab the area to be sampled. After swabbing the agar surface, place the swab in the nutrient broth and leave it there during incubation. You may need to break off part of the wooden handle to fit the swab into the nutrient broth tube. c. The plates and tube should be incubated at the approximate temperature of the environment sampled. Incubate bacteria from your body at or close to your body temperature. What is hu- man body temperature?(8) °C d. Incubate all plates inverted so that water will condense in the lid instead of on the surface of the agar. Why is condensation on the agar undesirable? (9) from any part etting a cotton er, swabbing en swabbing gar. Why oistened in m, discard atainer of e. Incubate all inoculated media at the appro- priate temperature until the next laboratory period agar your fingers.

Answer 1

C. Normal human body temperature is 37°C. In general microbial incubators are maintained at this temperature only.

D. Condensation of water on agar may interfere with the growth of bacteria. If we have pattern or streak or colony isolation on agar plate, it would be mixed by water.