1. Proteins l Made of Carbon, Hydrogen, Oxygen, Nitrogen (and sometimes sulfur) l Arranged from only 20 amino acids!!! (like the alphabet)

2. Amino Acids l Made up of 4 parts l Part 1 = Hydrogen atom l Part 2 = Amino group (NH 2 ) l Part 3 = Acid group (COOH) l Part 4 = R group (side chains that differ from amino acid to amino acid) l http://hyperphysics.phy- astr.gsu.edu/HBASE/organic/ami nostruct.html

4. Protein Structure l 1 amino acid linked to another by a peptide bond (see drawing on board) l Does this look familiar????? l DEHYDRATION SYNTHESIS

5. Protein Structure l Many amino acids linked together are a polypeptide chain l Chain folds up on itself to form a giant ball (like a mess of yarn) which forms the protein l There are four levels of protein structure

6. Protein Structure l Primary Level Polypeptide chain- like fruit frenzy on a string

7. Protein Structure l Secondary Level Chain coils around (like a spring) Called the alpha helix

8. Protein Structure l Tertiary Level Coil becomes folded up

9. Protein Structure l Quaternary Level Multiple chains join together

10. PROTEINS l Most diverse group of biological molecules l Enzymes l Structural l Transport l Nutritious l Regulatory l Defense l Function depends on structure

11. Enzymes- a special kind of protein l Special proteins - increase chemical rxn rates – called catalysts l Most biological rxns can’t take place without them

12. How Enzymes Work l Energy needed to start a reaction l Called ACTIVATION ENERGY l Enzymes lower this

13. How Enzymes Work l Enzymes help rxns occur at normal cell temps l Weaken chemical bonds l Heat does too- but heat not good for cells

14. How Enzymes work l Enzymes are specific- each helps only 1 reaction occur l What’s involved? l Substrate- what the enzyme acts on l Active site- where the substrate fits perfectly in to the enzyme l Like pieces of a puzzle

15. An enzyme at work