2. Regents Biology Proteins

3. Regents Biology 2006-2007 Proteins: Multipurpose molecules

4. 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

5. 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

6. Regents Biology Proteins  Building block = amino acid amino acid – amino acid – amino acid – amino acid – —N——N— H H H | —C— | C—OH || O R amino acids  20 different amino acids Amino acids: An amino group (NH2) An acid group (COOH) A Hydrogen atom And an “R” group

7. 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

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

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

10. 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

11. 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!

12. Regents Biology 2006-2007 Let’s EAT some Proteins!

13. Regents Biology Activities  demo raw egg vs. cooked egg  drop raw egg into boiling water, like egg drop soup  compare raw egg to hard-boiled egg  demo cheese-making with heated milk & vinegar  make yogurt