1. Chapter 3 Intro,3.1,3.2 Spider Webs and Carbon

2. Orb-Weaving Spider Web Contains carbon

3. Polymer Science U. of A.

4. Orb Spider Web

5. Spiders secrete their silk from glands located on their lower side

6. Silk being secreted from glands in the spigots (SEM x3,740)

7. Spinnerets

8. Web Design

9. Straight Strands Radial Dry Inelastic proteins

10. Radial Strands “Spiraling strand”-captures insects Wet Sticky Highly elastic (stretch up to 4X’s)

11. The web is started with a horizontal thread stretched between two supports. The spider lets out a thread that is carried to another support by a breeze or air current. The spider then pulls in the excess to stretch the thread taut.

12. Dragline being silked from spinnerets

13. The spider then moves to the center of the sagging, loose thread, and drops, letting out another thread and forming a ‘Y’.

14. When the spider reaches the anchor point, it walks down the support to affix the new thread to another support point. The spider will spin threads between anchor points to give the web a frame.

15. The spider makes the non-sticky scaffolding, from the outer edge to the center, attaching sticky threads that form the trap.

16. The spider cuts away the non-sticky scaffolding as it progresses toward the center. The whole process of building a web takes about a half hour.

17. Web Design

18. largest spigot produces the spider's safety line, called the dragline. The smaller spigots produce lots of short sticky threads that make a strong attachment point for other silk lines.

19. Coils..then straightens Normal – Stretched 5X - Stretched 20X

20. Spider web glue droplets SEM on a strand of spider silk

21. Why is there so little sag? Coiling and uncoiling of silk fibers When the prey is no longer pressing against the strand…the fluid’s surface tension “beads” and rewinds the fiber

22. The spider uses its rear legs to pull and stretch the coagulated silk from the spinnerets

23. What is Web Silk Made Of? the primary constituents of spider silk turn out to be the two simplest amino acids, glycine and alanine

24. "Dragline spider silk is actually stronger than Kevlar synthetic fiber- and Kevlar is several times stronger than steel"

25. Spider Silk Dragline silk at least 5X’s stronger than steel, 2X’s more elastic than nylon waterproof and stretchable.

26. Why don't spiders stick to their webs? Silk line with middle claw and bristles. Only a tiny area of its body in contact with the silk lines (the tips of its legs) + has a secretory lubrication on the claws

28. Spider Silk Research January 2002 spliced DNA from spiders into cells taken from hamsters and cows These cells produced spider silk proteins

29. Make Artificial Silk for: Artificial tendons and ligaments Surgical sutures Bulletproof vests Space Station Coatings Fishing line

30. USES -wear-resistant shoes and clothes -stronger ropes, nets, seatbelts, and parachutes -rust-free panels and bumpers for automobiles -improved sutures and bandages, artificial tendons and ligaments, and supports for weakened blood vessels. -soldiers and police long for bulletproof vests

31. Organic Compounds Contain carbon and synthesized by cells

32. Carbon 6 p 6 n 6 e-

33. Carbon can bond to 4 e- Total of 6 electrons 4e- in outer shell

34. Can bond to 4 H

35. Hydrocarbons Contain hydrogen and carbon

36. METHANE One carbon

37. Carbon Skeleton Carbon Chain Here with 6 carbons (hexane)

38. Unbranched

39. Can be branched Like here with isooctane (8 carbons)

40. Rings Cyclohexane

41. Aspirin Note the ring

43. Single bond (ethane) Double bond (ethene) Triple bond (ethyne)

45. Isomers Same molecular formula but different structure (orientation) All C 5 H 12