Question

Streak Place Isolation for Obtaining Pure Cultures Data Interpretation Please type the answers to the following questions below (double spaced) and attach the data collection sheets when you hand in this lab report. 2. When an agar plate is inoculated, why is the loop sterilized after the initial Inoculation is put on? 2. Define pure culture, a mixed culture? 3. Define a bacterial colony. List four characteristics by which bacterial colonies may be distinguished? 4. Why should a Petri dish not be left open for any extended period of time? 5. Why does the streaking method you used to inoculate your plates result in isolated colonies? 16. Why is it necessary to isolate individual colonies from a mixed growth? - Why was blood agar, rather than a nutrient agar plate used for the culture from your mouth? - Are a large number of microorganisms found in the mouth a cause for concern? Explain. How do microorganisms find their way into the mouth?

Answer 1

1) Loop is sterilized after the initial inoculation in order to prevent the contamination

2) Pure culture: In pure culture only single type of the species is present

Mixed culture:  In mixed culture minimum two types of species are present in the culture

3) Bacterial colony:  Bacterial colony is the clump of bacteria growing together in the agar plate.

They are distinguished by :

i) shape

ii) surface

iii) Pigmentation

iv)Opacity

4) Petri Dish should not be kept open because It may get contaminated by the Microorganisms present in the air and the Agar gel will dry up soon

5) streaking method: it is a type of technique that gives us the isolated colonies and these isolated colonies were grown separately.

6) To grow individual species.