Question

problem set 4: laboratory applications

1. in the cheek swab lab, methylene blue stain was used. explain:

• why this stain was necessary
• what cellular structures it would highlight
• why you might not see all organelles even with staining

Explanation:

• Necessity: Cheek cells are transparent, stain makes them visible under microscope.
• Structures highlighted: Nucleus as methylene blue binds to DNA/RNA in it.
• Not seeing all organelles: Some organelles are too small for light - microscope (used in cheek - swab lab), or their refractive index and staining properties don't allow easy visualization.

Answer:

• Why this stain was necessary: Cheek cells are transparent, and the stain makes them visible under a microscope.
• What cellular structures it would highlight: The nucleus, as methylene blue binds to DNA/RNA present in it.
• Why you might not see all organelles even with staining: Some organelles are too small to be seen with a light - microscope (commonly used in a cheek - swab lab), or their refractive index and staining properties do not allow for easy visualization.