1. Bio 3 – Enzyme Lab Part 1: Enzymes, cheese making, and fat digestion
An enzyme

2. Cheese making takes an hour an a half
Must begin the procedure before the lecture
Slowly heat the milk to 32°C.
Stir occasionally.
Add 1 ml of enzyme and stir for one minute.
Allow the beaker to sit undisturbed for about 30 minutes.

3. Globular proteins that facilitate reactions
Enzymes:
Globular proteins that facilitate reactions
Many reactions require energy to start
Enzymes reduce the energy required
Enzymes are Biological Catalysts
Initiate and increase the rates of reactions
Not consumed or altered
Coordinate production of molecules with need
Specific to a particular substrate

4. Substrate specificity is based on shape
Unique surface shape
Unique electromagnetic properties

5. How enzymes work Decrease Energy of Activation (EA) to start reactions
Simple example: spark plugs reduce EA
EA is absorbed by reactants
Destabilizes their bonds
Increases their reactivity
Enzymes do not supply energy
“Induced fit” lowers need for EA
Squeezes and aligns substrate(s)
Active site

6. Example: enzyme-mediated reaction

7. Sucrase enzyme (-ase indicates enzyme)1 3 2

8. 1
Sucrase catalyzes hydrolysis of sucrose (substrate) 3 2

9. Produces glucose & fructose (products)1
Produces glucose & fructose (products) 3 2

10. 1 3 2

11. 1 3 2

12. 1 3 2

13. 1 3 2

14. 1 3 2

15. Enzymes can be involved in:
1) Degradation: previous sucrase example
2) Synthesis:
3) Transformation:

16. Enzymes work best in optimal conditions
Can undergo > 1 million reactions / second
Thermal optimum
Excessive cold or heat decreases activity
Cold slows molecular motion
Too much heat DENATURES enzymes
Breaks hydrogen bonds that hold its shape

17. Gastric enzymes pH optimum Neutral (pH = 7) for many human enzymes
Exceptions:
Gastric enzymes
Enzymes of organisms in alkaline environments
Acid rain slows enzymes of aquatic organisms

18. Read pages 41-43 of the lab manual, then begin cheese making.

19. Replicate fat digestion in a test tube
Part 2: Lipid digestion
Today’s exercise:
Replicate fat digestion in a test tube
Same process occurs in your intestine
Add the following to each tube:
Tube 1: 3 ml of litmus cream + 6 ml of distilled water. Tube 2: 3 ml of litmus cream + 3 ml of distilled water + 3 ml of bile solution.
Tube 3: 3 ml of litmus cream + 3 ml of distilled water + 3 ml of lipase solution.
Tube 4: 3 ml of litmus cream + 3 ml of bile solution + 3 ml of lipase solution.
Groups A-D will incubate at different temperatures for 1 hr.

20. Lipid digestion occurs in your small intestine
Liver
Pancreas
(with lipase)
Gall bladder
(with bile)
Small intestine
(doudenum)

21. Lipid digestion by hydrolysis

22. Fatty acids disassociate in an aqueous solution
Carboxyl functional group =
HO-C-CH2-CH2-CH2-CH2-CH2 O = O
- O-C-CH2-CH2-CH2-CH2-CH2 H+
Hydrogen ion
Presence of H+ ion changes pH