1. Regents Biology Proteins

2. Regents Biology 2006-2007 Proteins: Multipurpose Molecules

3. Regents Biology collagen (skin) Proteins insulin Examples  muscle  skin, hair, fingernails, claws  collagen, keratin  pepsin  digestive enzyme in stomach  insulin  hormone that controls blood sugar levels pepsin

4. Regents Biology Proteins  Function:  many, many functions  hormones  signals from one body system to another  insulin  movement  muscle  immune system  protect against germs  enzymes  help chemical reactions

5. Regents Biology Proteins  Building block = amino acid amino acid – amino acid – amino acid – amino acid – —N——N— H H H | —C— | C—OH || O variable group amino acids  20 different amino acids There’s 20 of us… like 20 different letters in an alphabet! Can make lots of different words

6. Regents Biology Dipeptide = two amino acids bonded by a condensation reaction  Covalent bond called a Peptide Bond shown in lavender (?)

7. Regents Biology Proteins = Polypeptides  Polypeptide = Long amino acid chains… composed mainly of carbon, hydrogen, oxygen, and nitrogen

8. Regents Biology Amino acid chains  Proteins = amino acids chained into a polymer  Each amino acid is different  some “like” water & dissolve in it  some “fear” water & separate from it amino acid

9. Regents Biology Water-fearing amino acids  Hydrophobic  “water fearing” amino acids  try to get away from water in cell  the protein folds

10. Regents Biology Water-loving amino acids  Hydrophillic  “water loving” amino acids  try to stay in water in cell  the protein folds

11. Regents Biology pepsin For proteins: SHAPE matters! collagen  Proteins fold & twist into 3-D shape  that’s what happens in the cell!  Different shapes = different jobs hemoglobin growth hormone

12. Regents Biology It’s SHAPE that matters!  Proteins do their jobs, because of their shape  Unfolding a protein destroys its shape  wrong shape = can’t do its job  unfolding proteins = “denature”  temperature  pH (acidity) folded unfolded “denatured” In Biology, it’s not the size, it’s the SHAPE that matters!

13. Regents Biology

14. 2006-2007 Let’s EAT some Proteins!