If safranin was omitted from the endospore stain procedure, what color would the endospores appear under the microscope?

• A. Purple
• B. Green
• C. Colorless
• D. Red

Answer: (B)

Verified step by step guidance

1. Understand the purpose of each stain in the endospore staining procedure: malachite green is used to stain the endospores, and safranin is used as a counterstain to color the vegetative cells.
2. Recall that malachite green is a primary stain that penetrates the tough outer coat of endospores and stains them green, while safranin stains the vegetative cells red or pink.
3. Consider what happens if safranin is omitted: the vegetative cells will not be counterstained and therefore will not take up any color, becoming colorless or very faint under the microscope.
4. Since malachite green is not removed from the endospores during the decolorization step, the endospores will retain the green color regardless of the presence of safranin.
5. Conclude that without safranin, endospores will appear green, and vegetative cells will appear colorless under the microscope.