Test Correction Concerns

1. Test Correction Concerns Not all test corrections are earning credit…please take care to be complete in your responses! See me during office hours, etc. if you have questions. If you do your learning logs, please take the time to do your test corrections! I’m concerned with some test corrections that still show confusion on concepts…see me during office hours if you need help!!!

2. FINAL Unit 1 Test Grade Ranges • Overall: 36 – 112.5 • Period 2: 36 – 110 • Period 3: 59.5 – 109.5 • Period 5: 86.5 – 112.5 • Period 6: 44 – 110 • Period 8: 42.5 – 110 • *NOTE: The student who scored the lowest raw score (9/25 – 36%) on the multiple choice section ended up with a final overall grade of a ‘C’ on the test…due to completing a quality learning log and careful completion of test corrections!!!

3. Proteins Multipurposemolecules

4. Proteins • Most structurally & functionally diverse group • Function: involved in almost everything • enzymes (pepsin, DNA polymerase) • structure (keratin, collagen) • carriers & transport (hemoglobin, aquaporin) • cell communication • signals(insulin & other hormones) • receptors • defense (antibodies) • movement (actin & myosin) • storage (bean seed proteins)

5. Proteins • Structure • monomer =amino acids • 20 different amino acids • polymer =polypeptide • large & complex (3-D) molecules hemoglobin growthhormones

6. H O | —C— | H || C—OH —N— H Amino acids • Structure • central carbon • amino group • carboxyl group (acid) • R group (side chain) • different for each amino acid • confers unique chemical properties to each amino acid • like 20 different letters of an alphabet • can make many “words” (proteins) R amino = NH2 acid = COOH

7. H2O peptidebond Building proteins • Peptide bonds • covalent bond between NH2 (amine) of one amino acid & COOH (carboxyl) of another • C–N bond dehydration synthesis

8. Effect of different R groups: Nonpolar amino acids • nonpolar & hydrophobic Why are these nonpolar & hydrophobic?

9. Effect of different R groups: Polar amino acids • polar or charged & hydrophilic Why are these polar & hydrophillic?

10. Sulfur containing amino acids • Formdisulfide bridges • covalent cross links betweens sulfhydryls • stabilizes 3-D structure H-S – S-H

11. hemoglobin collagen Protein structure & function • Function depends on structure • 3-D structure • twisted, folded, coiled into unique shape pepsin

12. Primary (1°) structure • Order of amino acids in chain • amino acid sequence determined by DNA • slight change in amino acid sequence can affect protein structure & its function • even just one amino acid change can make all the difference!

13. Sickle cell anemia Hydrophilic! Hydrophobic!

14. Secondary (2°) structure • “Local folding” • folding along short sections of polypeptide • H bonds • weak bonds between R groups • -helix • -pleated sheet

15. Tertiary (3°) structure • “Whole molecule folding” • interactions between distant amino acids • hydrophobic interactions • nonpolar amino acids cluster away from water • H bonds & ionic bonds • disulfide bridges

16. Quaternary (4°) structure • More than one polypeptide chain bonded together • only then does polypeptide become functional protein hemoglobin collagen = skin & tendons

17. Protein structure (review) R groups hydrophobic interactions disulfide bridges (H & ionic bonds) 3° multiple polypeptides 1° amino acid sequence peptide bonds 4° 2° determinedby DNA R groups H bonds

18. Protein denaturation • Unfolding a protein • conditions that disrupt H bonds, ionic bonds, disulfide bridges • temperature • pH • salinity • alter 2° & 3° structure • alter 3-D shape • destroys functionality • some proteins can return to their functional shape after denaturation, many cannot