9. What type of m olecule is silk? What are the monomeric units of this polymer?

Question

9. What type of m olecule is silk? What are the monomeric units of this polymer?

10. Review the organic functional groups introduced in chapter 5 of 21 st Century Chemistry – the amines and carboxylic acids. Draw the amino acid glycine and the amino acid serine . Now bring them together to make a dipe ptide – the two amino acids are joined by a peptide bond.

11. How does artificial differ from synthetic ?

12. What is nylon 6,6? Show the structure and explain why it was named thus.

13. Draw and label the following organic functional groups that have been introduced so far in the text and this book , you should be able to recognize these groups when they appear in organic molecules: amine, carboxylic acid, alcoho l (hydroxyl), amide, benzene ring & phenol.

Explanation / Answer

9) Silk produced by the silkworm consists of two main proteins, sericin anf fibroin. Fibroin being the structural center of the silk and sercin being the stciky material surrounding it. Fibroin consists of amino acids Gly-Ser-Gly-Ala-Gly-Ala and forms beta pleated sheets. Hydrogen bonds form between the chains, side chains form above and below the plane of hydrigen bond network.

The monomer unit of silk is a tetrapeptide consistinf of 4 amino acids -[Gly-Ser-Gly-Ala]-n linearly coupled in this order. The high protein content (50% Glycine) which is the smallest amoinoacid , allows tight packing , so the fibres are strong and resistant to streching. The tensile strength is due to the high number of interseeded hydrogen bonds.

** Answering only first question due to policy and time constraints. Please help us help you by posting the questions individually. Sorry to dissapoint you.

Related Questions

Navigate

• Browse (All)
• Browse 9
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.