Question

what is the purpose of adding a strip of paper to the spore stain procedure?

select all that apply.

a. the paper allows for more contact time between the dye and spores.
b. the paper is protective to the scientist doing the stain.
c. the paper is sticky and removes live bacteria from the smear.
d. the paper helps hold stain away from the sample.
e. the paper keeps the dye from evaporating too quickly during the heating step.

Explanation:

Analyze the role of paper in endospore staining

In the Schaeffer-Fulton endospore staining method, a small piece of blotting paper or paper towel is placed over the bacterial smear before applying the primary stain (malachite green) and heating. The paper acts as a reservoir that holds the liquid dye directly on top of the specimen, ensuring continuous contact between the dye and the highly resistant endospores.

Evaluate evaporation prevention

During the steaming/heating step, the liquid dye is prone to rapid evaporation and drying out, which can ruin the preparation. The paper strip retains the moisture and prevents the dye from evaporating too quickly, keeping the smear wet throughout the heating process.

Assess incorrect options

• Option B is incorrect because the paper does not serve a protective safety function for the scientist.
• Option C is incorrect because the paper is not sticky and is not used to remove bacteria.
• Option D is incorrect because the paper is meant to keep the stain in contact with the sample, not hold it away.

Answer:

• A. The paper allows for more contact time between the dye and spores. (Correct answer)
• B. The paper is protective to the scientist doing the stain.
• C. The paper is sticky and removes live bacteria from the smear.
• D. The paper helps hold stain away from the sample.
• E. The paper keeps the dye from evaporating too quickly during the heating step. (Correct answer)