1. Bio 3 – Enzyme Lab Read pages 41-43 in lab manual
Part 1: Enzymes, cheese making, and fat digestion
An enzyme

2. Cheese making takes about 2-1/2 hours
Must begin the procedure before lecture
Lectures will be given during “down times”
Procedure:
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 covered with foil. Then interrupt lecture-
lecture to begin 30 minutes of cooking.
Turn off hotplates when done cooking
Cheese making questions are on page 48.

3. Globular proteins that ________ reactions
Lab Lecture
Enzymes:
Globular proteins that ________ reactions
Most reactions require energy to start
Enzymes reduce the energy required
Enzymes are Biological ________
Initiate and increase the ______ of reactions
___ consumed or altered
Coordinate production of molecules with need
Specific to a particular substrate

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

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

6. Example: enzyme-mediated reaction

7. Sucrase enzyme (-ase indicates enzyme)
Catalyzes hydrolysis of sucrose (_________)
Produces glucose & fructose (products)

8. Enzymes can be involved in: 1) Degradation: previous sucrase example
2) Synthesis:
3) Transformation:
E.g., sex hormones

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

10. _______ enzymes pH optimum Neutral (pH = 7) for many human enzymes
Exceptions:
_______ enzymes
Enzymes of organisms in alkaline environments
Acid rain ______ enzymes of aquatic organisms

11. Enzymes Lab Part 2: Lipid digestion
Read pages Do not begin procedures.

12. Today’s exercise:
Replicate fat digestion in a test tube
Same process occurs in your ________

13. Lipid digestion occurs in your small intestine
Liver
Pancreas
(with ______)
Gall bladder
(with ____)
Small intestine
(doudenum)

14. Lipid digestion by hydrolysis

15. Fatty acids disassociate in an aqueous solution
___________ functional group =
HO-C-CH2-CH2-CH2-CH2-CH2 O = O
- O-C-CH2-CH2-CH2-CH2-CH2 H+
____________ ion

16. Roles of ingredients:
Litmus cream:
Cream: source of _______ (triglycerides)
Litmus powder: changes color with ___
Red = acidic, violet = basic
Bile:
Emulsifies fats
Reduces large globs to small ________
Lipase:
Enzyme that facilitates _________ of lipids
Optimal pH and temp same as in intestine
Distilled water:
“Filler”
All free ions removed

17. Groups A-D will incubate at different temps (see pg 45).
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.
Incubate for 1 hr