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Topics for Today

Topics for Today. Natural Curls?. Topics for Today. How do proteins get their shape?. Chapter 12. 12.3 Cracking the chemical code (p. 539 on proteins only). Chapter 5. 5.6 The role of hydrogen bonding. Topics for Friday. Closing Remarks Quiz #11 (Don’t be late!). Topics for Friday.

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Topics for Today

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  1. Topics for Today • Natural Curls?

  2. Topics for Today • How do proteins get their shape?

  3. Chapter 12 • 12.3 Cracking the chemical code (p. 539 on proteins only)

  4. Chapter 5 • 5.6 The role of hydrogen bonding

  5. Topics for Friday • Closing Remarks • Quiz #11 (Don’t be late!)

  6. Topics for Friday • If you are > 5 minutes late… No quiz for you!

  7. Announcements! HW 5 due tomorrow Psst… easy 10 points!

  8. Announcements! NOT here! Final Exam Friday, May 18 at 12:25 pm in 113 Psychology!

  9. Announcements! Final Exam Don’t forget about the essay!

  10. Ever wondered how we measure metals in atmospheric PM? NO! Still, you’re all invited to a special talk on Friday!!!

  11. Dr. Majestic Talks About His Research! 12:05 pm THIS Friday; 102 Water Science and Engr Lab!!

  12. Topics for Today • How do proteins get their shape?

  13. Review What is a protein??

  14. A polymer of amino acids!! …amide-ala-amide-gly-amide-leu-amide-ile-amide-glu-amide-arg-amide-asp-amide-ala…

  15. Keratin, … A protein that contains a high content of cysteine.

  16. Glycine (gly) Alanine (Ala) Valine (Val) Leucine (Leu) Isoleucine (Ile) Proline (Pro) Tryptophan (Trp) Phenylalanine (Phe) Serine (Ser) Threonine (Thr) Tyrosine (Tyr) Aspartic acid (Asp) Glutamic acid (Glu) Asparagine (Asn) Glutamine (Gln) Lysine (Lys) Arginine (Arg) Histidine(His) Cysteine (Cys) Methionine (Met)

  17. Cysteine R = –CH2–S–H • Methionine R = –CH2–CH2–S–CH3 Contains sulfur!!

  18. Keratin, … Where is keratin found? Hair!

  19. Hair • ~90% protein (keratin)

  20. Hair • Also contains melanin Skin pigment

  21. Keratin • The chains of amino acids form a coil Why a coil?

  22. The side chains give the protein its shape!

  23. Keratin • Nonpolar R groups on the outside of the coil R R R R R Water repelling (hydrophobic)

  24. Keratin What about the R groups inside? R R R R R

  25. Keratin What about the R groups inside? R R R R These help give hair its structure R

  26. What gives hair its structure? R groups that … (1) contain –SH and form disulfide bonds (2) are ionic and attract each other (3) hydrogen bond to each other

  27. What gives hair its structure? R groups that … (1) contain –SH and form disulfide bonds (2) are ionic and attract each other (3) hydrogen bond to each other

  28. .. .. What do we know about water? Review O H H • 1) It’s bent • 2) It’s polar • 3) Polar things dissolved in water • 4) Formed from acid-base reactions • 5) Formed from making Nylon and PET • 6) Anywhere from ½ to ¾ of our body • 7) Forms ions in small amounts

  29. What else do we know about water?

  30. Hydrogen bonds! Fig.05.10 What are H-bonds?

  31. δ- δ- Fig.05.10 δ+ δ+ δ+ δ+ δ- δ+ δ+ δ- δ- δ+ δ+ δ+ δ+

  32. Fig.05.10

  33. Hydrogen bonds Need a dipole!! • Not really bonds, at all! Just a strong attraction!

  34. Can non-water molecules H-bond?

  35. δ- δ- Fig.05.10 Hydrogen bonds? δ+ δ+ δ+ δ+ .. δ- N H δ+ δ+ δ+ δ- δ- δ+ δ+ δ+ δ+

  36. Hydrogen bonds… δ- δ- Fig.05.10 δ+ δ+ δ+ δ+ .. δ- N H δ+ δ+ δ+ δ- δ- δ+ δ+ δ+ δ+

  37. H bonds • Occur when H is attached to an electronegative atom such as O, N or F. page 231

  38. Amino Acids Glycine (gly) Alanine (Ala) Valine (Val) Leucine (Leu) Isoleucine (Ile) Proline (Pro) Tryptophan (Trp) Phenylalanine (Phe) Serine (Ser) Threonine (Thr) Tyrosine (Tyr) Aspartic acid (Asp) Glutamic acid (Glu) Asparagine (Asn) Glutamine (Gln) Lysine (Lys) Arginine (Arg) Histidine(His) Cysteine (Cys) Methionine (Met) Which amino acids will H-bond?

  39. Hydrogen bonds –O NH

  40. What gives hair its structure? R groups that … (1) contain –SH and form disulfide bonds (2) are ionic and attract each other (3) hydrogen bond to each other

  41. Cysteine H O | // H2N — C — C | \ CH2 OH | SH

  42. Amide Backbone R = CH2– SH – SH HS – – SH HS – – SH HS – – SH HS –

  43. Disulfide bonds Not easily broken!! – S – S – – S – S – – S – S – – S – S –

  44. Disulfide bonds – S – S – – S – S – A “permanent” – S – S – – S – S –

  45. Break the disulfide bonds! – SH HS – – SH HS – Reset the strands – SH HS – – SH HS –

  46. – S – S – – S – S – – S – S – – S – S –

  47. Summary A permanent • Break the S – S bonds • Wrap hair around a curler • Reform S – S bonds to permanently change the shape

  48. What gives hair its structure? R groups that … (1) contain –SH and form disulfide bonds (2) are ionic and attract each other (3) hydrogen bond to each other

  49. (3) Acidic REVIEW • R group contains carboxylic acid

  50. Aspartic acid REVIEW

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