Protein (polypeptides, enzymes)

1. Protein(polypeptides, enzymes) Pg. 19 – 29 (same pages for the next few classes)

2. Building proteins • Proteins are polymers of amino acids • There are ~21 standard (natural) amino acids • 9 are essential • 12 are non-essential What does this mean?

3. The vegan dilemma… Animal foods contain all essential amino acids(Plant-derived foods do not)

5. Protein structure • Proteins vary enormously in size • Smallest protein = 20 amino acids • Large protein – 27,000 amino acids • The order of the amino acids determines the structure, properties and function of the protein peptide bond

6. Protein structure • There are 4 levels of protein structure • Primary structure • amino acid sequence • Secondary structure • simple 3D arrangements Alpha helix Beta sheet

7. Protein structure • Tertiary structure • 3D protein structure

8. Quaternary structure • multiple proteins combined to make 1 functional unit

9. Protein function • Proteins can serve multiple functions • Structural proteins • Muscle, bone, hair skin • Hormones • Testosterone, estrogen, insulin • Enzymes • “Big molecules that do stuff” (eg. accomplish or aid in most cellular reactions)

10. Denaturation The shape of a protein can be altered by heat or radiation This denaturation causes the protein to unfold/uncoil and lose functionality This change is usually permanent

11. Denaturation

12. Testing for proteins • Biuret solution • Turquois solution becomes violet

13. Try this… • Pg. 27 • #22 – 24