Which one of the following statements comparing alpha keratin and silk fibroin is true?
A) Both have covalently cross-linked strands.
B) Both are primarily -helical in character.
C) Both fibers are intracellularly located.
D) Both fibers are heavily stabilized by hydrogen bonds.

Question

Which one of the following statements comparing alpha keratin and silk fibroin is true?
A) Both have covalently cross-linked strands. 
B) Both are primarily -helical in character. 
C) Both fibers are intracellularly located. 
D) Both fibers are heavily stabilized by hydrogen bonds.

Quizplus · Accepted Answer

Both alpha keratin and silk fibroin are heavily stabilized by hydrogen bonds between the peptide chains. However, they differ in their covalent cross-linkages (alpha keratin has disulfide bonds while silk fibroin has non-covalent linkages) and secondary structure (alpha keratin has a predominantly alpha-helical structure while silk fibroin has a beta-sheet structure). Additionally, silk fibroin is secreted extracellularly by silkworms while alpha keratin is primarily found in skin, hair, and nails of animals.

Which One of the Following Statements Comparing Alpha Keratin and Silk