Which element is added to chitin's monomer?

Which element is added to chitin's monomer?

• A. Oxygen
• B. Nitrogen
• C. Phosphorus
• D. Carbon

Answer: (B)

Chitin is built from N-acetylglucosamine units, which are glucose molecules modified by an acetylated amino group. That modification introduces nitrogen into the monomer, because the amino group contains nitrogen. So nitrogen is the element added to the monomer to form chitin. Oxygen is already part of the sugar ring and its substituents, phosphorus isn’t involved in chitin, and carbon is the existing backbone of the sugar—what makes chitin unique is the nitrogen-containing acetylamino group.

Chitin is built from N-acetylglucosamine units, which are glucose molecules modified by an acetylated amino group. That modification introduces nitrogen into the monomer, because the amino group contains nitrogen. So nitrogen is the element added to the monomer to form chitin. Oxygen is already part of the sugar ring and its substituents, phosphorus isn’t involved in chitin, and carbon is the existing backbone of the sugar—what makes chitin unique is the nitrogen-containing acetylamino group.