Lab Activity 7 – Preparation of a Pure Culture

The Streak Plate Technique

Plates were streaked and incubated for 48 hours.

Figure 1. Streak plates using a mixed culture.

 

Questions

  1. Above are four examples of streaked plates. Each plate was streaked with a mixed culture of M. luteus and S. marcescens. For each plate discuss the following;
    1. How many different types of bacteria are visible?
    2. How many single colonies are visible?
    3. Is it appropriate for preparing a pure culture? Why or why not?
    4. Discuss the technique or method used. Was it the right technique? If the technique was incorrect, what was done incorrectly?
  2. Compare and contrast the three techniques used to isolate pure. Be sure to discuss the method and the end results. Remember when comparing and contrasting be sure to mention similarities and differences.