1112 Salivary Enzyme Lab

Human BiologyName Date

Enzyme Concentration . . . what does it matter?

Background Information : Many different reactions are necessary for the life and growth of plants and animals. There are compounds that our body produces that make it possible for these reactions to occur in a timely fashion. We call these compounds “catalysts”, but in living organisms we refer to these compounds as enzymes. The word “enzyme” comes from the Greek language and means “in yeast”. Go to this website and read about enzymes : http://en.wikipedia.org/wiki/EnzymeAnswer the following questions after your reading :(a) How do enzymes work? ( 2 pts)

(b) Are enzymes used up in a chemical reaction? ( 2 pts)

(c ) Would an enzyme that breaks down hamburger, would it also break down the hamburger bun? Why? Explain your answer. ( 5 pts)

(d) Name and describe some factors which can affect enzymes . ( 4 pts)

Because they are catalysts, enzymes are not affected not affected by the reactions that they enter into. They are harmed only by wear and tear and by poisons. A lot of questions can be raised about enzymes: Does temperature influence their effect? Does even more enzyme mean an even faster reaction? How specific are enzymes? What are enzymes made of? In this experiment, we will be answering one of those questions, however, I suspect you can figure out the answer to the other questions, after completing this activity, because you also will have discovered some of the chemical properties of the enzymes from the readings in this unit.

The enzyme you will be experimenting with is salivary amylase, the main enzyme in your saliva. GROSS! Not really, just make sure you have not eaten anything within the last hour, rinse your mouth our with some water, and you are ready to go! You may wish to work with a partner on this . .. it might be especially helpful for Part two.

MaterialsYou will need to obtain/purchase the following materials. ( if you live in the Spokane area . .. you may come by my classroom and I can give you some of the items . . . but you will need to purchase some of the items, nevertheless)

Important safety warning: While you are doing this lab, please use a pair of Safety glasses or goggles. This is important in terms of splash and spills. If you have problems with this, please contact me asap!

Small glass measuring cup that measures in milliliters . . . see the accompanying measuring chart at the end of this lab!

Human Biology/ Enzyme Lab

http://en.wikipedia.org/wiki/Enzyme

7 – 10 vials, the best thing would be empty pill bottles if available, the other option would be small Dixie cups or contact me!

Plastic drink cups with a 250 ml capacity . . . they work well as beakers as well as to hold the tubes.

Clean rubber band

Coffee stirrers . . . or clean popsicle sticks

Glucose test strips ( Can be purchased at Walgreens, Diastix --$10.99 for 50 strips . . . if you know of another student that is taking the course, you could possible split the cost on these items)

Tincture of Iodine ( Again at Walgreens 1.0 oz for $3.49—can be diluted by ½ to make a working solution). Be careful as this is toxic!!!!

Distilled water ( about $1.00 at the grocery store)

2 clean eyedroppers ( again available at the Pharmacy, and it is important that these are clean!)

A sharpie pen to mark your containers and tubes

Starch suspension ( The quickest is to purchase a can of Faultless—Regular Spray starch—fill a small plastic cup – capacity about 250 mls—half full of water, then spray the starch into the water , about 2 -3 seconds, swirl to mix). Once this is made, you can store this in a used/empty plastic water/pop bottle that has been cleaned out.

Watch with a second hand.

It is important that you assemble the above equipment and solutions prior to starting this activity. Best place to complete this would be in the kitchen, on a stable surface.

ProcedurePart One—What does Salivary Amylase do?

1) Label a clean vial/ test tube “Saliva”. Chew on a clean rubber band ( this usually works well) to produce saliva, and collect about 5 ml of saliva. It is important that you reduce the amount of bubbles in your sample of saliva, so please do not include the bubbles as part of your volume of saliva! Add about an equal amount of distilled water to make about 10 mls of solution. Set this aside. You will need this mixture for the first part of the experiment.

2) How does starch react with iodine? Using another clean vial add about 5 ml of the starch suspension to the tube. Record the color of the starch solution in the Table 1. Next add 2 drops of the iodine solution. Swirl carefully to mix, record this color in Table 1.

3) In another clean vial, add 5 ml of the starch suspension. To this add 2 mls ( about 40 drops ) of the saliva suspension. Swirl to mix, set aside. After five minutes, add 2 drops of the iodine solution. Has anything happened? How does this color compare to the color of the solution from #2 above? Record your results in table 1. If needed clean your vials/test tubes . . .rinse and dry them.


4) In a clean vial, add 5 mls of the starch suspension. To this add 2 mls ( about 40 drops) of the saliva suspension. Swirl to mix, set aside. Wait about ten minutes. Then using one of the Diastix strips, test the mixture and based on the bottle labeling, record your results in Table 1. Discard the strip, and clean the vials.

Table 1 ( 10 points) Tube # Contents Color before

adding iodineColor after

adding iodineWhat might this tell you?

1 Starch + iodine

2 Starch + saliva + iodine

3

Starch + saliva (use the diastix after 10 minutes)

Record your observations here :

You will not add iodine, but will use the diasix—record what happened after 10 minutes :

Be sure that you have recorded all of the data, then clean all of the test vial/tubes for the next part. Gear up . . . we will need more saliva!!!!


Part Two: What , if anything, does the amount of enzyme have to do with the rate of the reaction?

1) Label a clean vial/test tube 1:2. Chew on a clean rubber band to produce saliva, collect about 6 ml in the tube. It is important that you reduce the amount of bubbles in your sample of saliva, so please do not include the bubbles as part of your volume of saliva! Add 6 ml of distilled water. This gives you a 1 : 2 ( Said as a “one to two” dilution). Often times this said to be a one part saliva to two parts solution mixture. Swirl or mix the tube well, then place in a cup.

2) We are going to dilute our enzyme , so please carefully follow the procedure that follows. Label three more vials/test tubes in the following manner using the sharpie : 1 :10, 1 :100, and 1 : 1000. To get the 1 :10 dilution, use the dropper to transfer 2mls ( 40 drops) of the 1 : 2 dilution into the 1 : 10 test tube. Add 8 mls of distilled water to get a 1 :10 dilution. Get the 1 :100 and 1:1000 dilutions by following the illustration below and the directions pictured : It is important that you follow these diultions to obtain the proper concentrations. Make sure that you are labeling each of the vials/test tubes.

Use the diagram to assist you in the dilution of the enzyme into to the various vials/ test tubes.

3) Now add 5 mls of the starch suspension to each of the four test tubes. See the illustration below to help you with the procedure.

Notice that you will adding the same amount of starch

solution to each of the enzyme dilutions. Measure carefully!!!!

Important step!!!!! Then, every 2 minutes for 20 minutes, using the diastix strips, test each tube for the presence of sugar ( glucose). Record your data in Table 2. Use the guide on the side of the Diastix container to help you determine the presence of sugar.


As you complete the table, try to be as descriptive as you can as far as the presence and/or amount of sugar (glucose) present in each of the tubes.

When you have recorded all of the data, please discard the strips, you can pour the vial’s/tube’s contents with plenty ofwarm water.

If you are not repeating the lab, then all equipment can be discarded. Please clean your “lab area” as well thoroughlywashing your hands. Thank you!

Table 2 ( 10 points)

Amount of Enzyme Activity

Time ( In minutes)

DILUTION RATE OF AMYLASE1: 2 1: 10 1: 100 1: 1000

2

4

6

8

10

12

14

16

18

20

Next proceed to the Analysis questions, this will tell your level of understanding of this activity and to some degree how enzymes function.


Analysis Questions

1) In Part One you tested startch and iodine, what happened when these were mixed together? ( 3 pts)

2) Again, thinking about Part one, you then mixed starch and saliva, then finally added iodine. What happened here? What does this tell you about the affect of saliva on starch? ( 3 pts)

3) Lastly, in Part one, you mixed starch and saliva, waited a bit, then used the diastix. What did you find out in this procedure? ( 3 pts)

4) So to answer the question : What does Salivary amylase do? Write a 2 – 3 sentence response below telling me what you have learned in Part One. ( 10 pts)

5) Now considering Part Two of the Lab. . . . which dilution first showed a positive test for sugar ? ( 3 pts)

6) Which dilution showed a positive test for sugar, last ? ( 3 pts)

7) In which dilution did the reaction proceed most rapidly? ( 3 pts)

8) In which dilution did the reaction proceed least rapidly? ( 3 pts)

9) How does diluting the concentration of salivary amylase influence its ability to break down starch? ( 5 pts)

10) Consider the setup of the experiment. How can you be sure that the results are due only to the diluting of saliva with distilled water? ( 5 pts)

11) Propose an experiment that you could perform that would test the affect of temperature on salivary amylase. ( 10 pts)


12) In the space provided, write a brief paragraph ( 150 – 250 words) telling me what you have learned in performing this experiment. ( 25 pts)


Measuring Device equivalencies Use this chart to help you with measuring of both volume and mass . . . .

Cup Fluid ounces Tablespoon Teaspoon Milliliters Drops1c 8 oz 16 TBSP 48 tsp 237 ml ?¾ c 6 oz 12 TBSP 36 tsp 177 ml ?

2/3 c 5 oz 11 TBSP 32 Tsp 158 Ml ?1/2c 4 oz 8 TBSP 24 Tsp 118 Ml ?1/3 c 3 oz 5 TBSP 16 Tsp 79 Ml ?¼ c 2 oz 4 TBSP 12 Tsp 59 Ml ?

1/8 c 1 oz 2 TBSP 6 Tsp 30 Ml ?1/16 c 0.5 oz 1 TBSP 3 Tsp 15 Ml ?1/32 c 0.25 oz 0.5 TBSP 1.5 Tsp 7.5 Ml ?

You will need a medicine dropper of some sort. These are available in the pharmacy of any grocery store, usually as a way to measure liquid medicines ( cough syrups and such) for small children and infants. If you cannot find this, ask the pharmacist.

Important measure information is this :

20 drops of a liquid is equivalent to 1 ml ( milliliter). This will help you with measuring. Hold the dropper in the vertical position when measuring to ensure that drops are about the same size.

Other important information : 1 teaspoon of sugar ( sucrose) = 4 grams . This means that if you need 2 grams of sugar, you would need ½ tsp, for 1 gram you would need ¼ tsp sugar. Since we are not doing “quantitative” experiments—this approximate value will work.


1112 Salivary Enzyme Lab

Documents

Transcript of 1112 Salivary Enzyme Lab