LG: How do enzymes facilitate chemical reactions? 12/3/2012

1. LG: How do enzymes facilitate chemical reactions? 12/3/2012

2. LG: How do enzymes facilitate chemical reactions? 12/3/2012 • Do Now: Complete the following chart.

3. Enzyme • CATALYST – substance that affects rate of chemical reaction (speed up) • Is not changed during use • May be recycled (used again) • Protein molecule • Used in digestion, synthesis, cellular respiration, and photosynthesis • End in –ase(ex: lipase, amylase, lactase, DNA polymerase…)

4. Nothing works without enzymes • How important are enzymes? • all chemical reactions in living organisms require enzymes to work • building molecules • synthesis enzymes • breaking down molecules • digestive enzymes

5. How does enzyme work? • ****Enzymes are not changed by the reaction (can be reused!)

6. It’s shape that matters! • Lock & Key model • shape of protein allows enzyme & substrate to fit • specific enzyme for each specific reaction Substrate

7. Experiment

8. Experiment • Hand = enzyme • Thumb+index finger = enzyme’s active site • Toothpicks = substrates • Breaking the toothpick in two pieces = enzyme reaction

9. Experiment • Part A- rate of product formation in an Enzyme-facilitated reaction (normal enzyme activity) • Part B- effect of substrate concentration on enzyme activity • Part C- effect of temperature on enzyme activity

10. Class Data • Part A: Normal enzyme activity

11. Class Data • Part B- effect of denaturation on enzyme activity

12. Class Data • Part C:effect of substrate concentration on enzyme activity

13. Analysis/what affects enzyme activity? • Temperature Optimum temperature 35°- 40°C (body temp = 37°C)

14. 2. pH • changes in pH changes protein shape • most human enzymes = pH 6-8 • depends on where in body • pepsin (stomach) = pH 3 • trypsin (small intestines) = pH 8

16. 3. Substrate concentration

17. For enzymes…What matters? SHAPE!