Question

1. what is the counterstain used in the acid - fast stain? a) safranin b) malachite green c) methylene blue d) crystal violet 6. in the schaeffer - fulton method, what is the primary stain? a) safranin b) carbolfuchsin c) methylene blue d) malachite green 7. what is the purpose of steaming in endospore staining? a) to fix the smear b) to decolorize endospores c) to soften the capsule d) to allow stain penetration into spores

Explanation:

• For question 5: In acid - fast staining, safranin is the counterstain. It stains non - acid - fast cells red.
• For question 6: In the Schaeffer - Fulton method for endospore staining, malachite green is the primary stain which stains endospores green.
• For question 7: Steaming in endospore staining is to allow the stain (malachite green) to penetrate into the tough - walled spores.

Answer:

1. a) Safranin
2. d) Malachite green
3. d) To allow stain penetration into spores