Proteins

1. Proteins

2. Proteins: Multipurpose molecules

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

4. 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. H | —C— | H amino acid amino acid amino acid amino acid amino acid – – – – C—OH —N— O || H Proteins • Building block = amino acids • 20 different amino acids There’s20 of us… like 20 differentletters in analphabet!Can make lots of differentwords variable group

6. amino acid amino acid amino acid amino acid amino acid 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

7. Water-fearing amino acids • Hydrophobic • “water fearing” amino acids • try to get away from water in cell • the protein folds

8. Water-loving amino acids • Hydrophillic • “water loving” amino acids • try to stay in water in cell • the protein folds

9. Ex)collagen For proteins: SHAPE matters! • Proteins fold & twist into 3-D shape • that’s what happens in the cell! • Different shapes = different jobs **Fibrous** ***Globular*** Examples: growthhormone hemoglobin pepsin

10. 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) unfolded“denatured” In Biology, it’s not the size, it’s the SHAPEthat matters! folded

11. Let’s EAT some Proteins!

12. 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