2. Proteins Name__________

3. Dietary Sources of Proteins  Fish, meat, nuts, beans, dairy products, some whole grains are high in protein

4. 2006-2007 Proteins: Multipurpose molecules Vary widely in their size, shape, structure and function Contain C, H, O, N Organic Although 70% of your body is made of water, most of the other 30% is protein.

5. Proteins  Many functions:  signalling  Hormones are chemical signals from one body system to another Ex) Insulin  movement  Muscle proteins can contract (squeeze)  protection  Antibodies (immune system) protect against germs  chemical reactions in the body (metabolism)  Enzymes help to speed up chemical reactions  Can be used as an energy source but only as a last choice if no carbs or lipids are available.

6. 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

7. Proteins  Building block (monomer) = amino acids  20 different amino acids exist  Plants can make all of them  Your body can only make some and must get others from food There’s 20 of us… like 20 different letters in an alphabet! Can make lots of different words

8. Examples of Amino Acids

9. Amino acid chain = polypeptide  A lot of variety in proteins because each amino acid has a different R group. amino acid  Polypeptide = polymer  Contains many amino acids bonded together by dehydration synthesis

10. Amino Acids bond to form a polypeptide which folds to become a protein

11. Peptide Bond = covalent bond between two amino acids Remember: Dehydration Synthesis joins monomers! Remember: Hydrolysis breaks up polymers! Peptide bond

12. Polypeptide Example This one contains 6 amino acids. Alanine Glycine Tyrosine Glutamic Valine Serine Acid

13. Folding  Protein = a properly folded polypeptide  A protein cannot do its job until its properly FOLDED. Chain  coil  fold  sometimes join multiple chains

14. 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

15. 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”  High temperature  Extremes in pH (acidity) folded unfolded “denatured”