PREVIOUSLY ASKED IN:
PSC Miscellaneous Prelims 2018
Answer
Finger nails
Explanation
Human hair and fingernails are both primarily made of the same tough, structural protein called Keratin. Keratin is a type of fibrous protein that forms the main structural constituent of hair, feathers, hoofs, claws, and horns in various animals. It provides strength and resilience, protecting epithelial cells from damage or stress.
Key Points
- > Both hair and nails are made of a protein named Keratin.
- > Keratin is a tough, fibrous structural protein.
- > It is also the key structural material making up the outer layer of human skin.
- > Animal horns, hooves, claws, and feathers are also composed of keratin.
- > Teeth are made of calcified tissues (dentin and enamel), not keratin.
- > Tooth enamel is the hardest substance in the human body.
- > Cutting hair and nails does not cause pain because they consist of dead keratinized cells.
Additional Information
Composition of Various Body Parts
| Body Part | Primary Substance / Component |
|---|---|
| Hair & Nails | Keratin (Protein) |
| Tooth Enamel | Calcium Phosphate (Hardest substance) |
| Bones | Calcium and Phosphorus (Ossein protein) |
| Muscles | Actin and Myosin (Proteins) |
| Skin | Melanin (Pigment) and Collagen (Protein) |
Memory Tips
- Painless Pair: Think about what body parts you can trim with scissors or clippers without feeling pain—hair and nails. They share the exact same structural protein.