Example Answers to Endospore Stain Questions PDF

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lab micro 234 example homework questions and answers...

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Endospore Stain Questions 1.

What is the function of an endospore stain? The endospore stain is used to determine if endospores are present in a bacterial smear.

2.

Is the endospore stain technique an example of a simple stain or a complex stain? The endospore stain is a complex staining technique. Additionally, it is an example of a differential stain.

3.

How long is the heat-fix step for smears used in the endospore stain? Why is this done? The heat fix step is extended to at least two minutes prior to performing the endospore stain. This extended heat fix is used to soften the endospore coat, a tough layer of keratin, to help the primary stain penetrate the endospore coat.

4.

What is the primary stain in the endospore stain? What cellular structure does it stain? Malachite green is the primary stain used in the endospore stain. Malachite green is used to stain endospore coats.

5.

What is the decolorizer used in the endospore stain? Water is used as the decolorizer in the endospore stain protocol.

6.

What is the counterstain used in the endospore stain? What is stained by this reagent? Safranin is used as the counterstain during the endospore stain. Safranin is used to stain vegetative cells.

7.

You observe no green ovals, only pink cells, after a correctly performed endospore stain. Does this indicate that the bacterium is Gram –ve? Explain your answer. No, this result indicates that endospores are not present. Regardless of whether a bacterium is Gram +ve or Gram -ve, vegetative cells will appear pink after the endospore stain.

8.

You are working with a known Gram –ve bacterium, would you expect it to produce endospores? Explain your answer. No, endospores are not expected to be produced. There are no Gram -ve bacteria that are known to produce endospores, endospore production is limited to certain families of Gram +ve bacteria.

Endospore Stain Results Questions 1.

What are your observations and conclusions for this correctly performed endospore stain? Observation Blue-green ovals are present, pink bacillus shaped cells Conclusion Endospores are present

2.

What are your observations and conclusions for this correctly performed endospore stain? Observation Blue-green ovals are absent (not present), pink bacillus shaped cells Conclusion Cells are bacillus in shape

3.

What are your observations and conclusions for this correctly performed endospore stain? Observation Blue-green ovals are present, pink bacillus shaped cells Conclusion Endospores are present...