The Slippery Shield: teacher key

Boogers and Snot, grade 9 edition, written for 9th grade. Mucus is about 98 percent water, and a protein called mucin gives it its gel-like feel. Learn how the nose sweeps mucus clean and how scientists found out.

Read the book. Print this page for the key.

Questions and answers

1. About how much of healthy airway mucus is water?
   • About 0.7 percent
   • About 98 percent (answer)
   • About 70 percent
2. Why does mucus need water?
   • Cilia need the airways hydrated to work properly (answer)
   • They are made of salt
   • They stop germs by freezing them
3. What can a cold virus do to the cilia in the nose?
   • Make them grow longer
   • Slow them, and the effect can last several weeks (answer)
   • Turn them into goblet cells
4. What did the older scanner test follow in the nose?
   • A drop of mildly radioactive fluid (answer)
   • A tiny camera
   • A drop of dye in the stomach
5. Without its sugars, what does a mucin protein do?
   • It grows longer
   • It folds into a ball and holds less water (answer)
   • It turns into a cilium
6. What does hydrated mean?
   • Full of water (answer)
   • Very old
   • Covered in hair

Words

• mucin: mucus gel protein
• cilia: tiny sweeping hairs
• microbiome: community of microbes
• antibodies: germ-finding proteins
• hydrated: full of water