Figure 4.23. Electron micrograph of a cluster of E. Coli
bacteria. Each individual bacterium is oblong shaped.
10,000X
Photo by Wikimediacommons.org.
Thinking Like a Biotechnician
Data Analysis/Conclusion
Do the cells in the culture appear to be Gram– bacilli? Give evidence for your answer. Describe
the issues that make it difficult to distinguish tiny bacteria cells through microscopy and Gram
staining.
1. Why is it important to have a “Fix” step (2g)? What would happen if you didn’t “fix” the sample?
2. When viewing the cells on 1000X, all the cells look melted together and their shape is
impossible to distinguish. Explain what may have happened to the cells to change their shape.
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Chapter 4 Laboratory Manual