IB 1108 L08 Enzymes - Answer sheet PDF

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PRE-LAB QUESTIONS 1. How could you test to see if an enzyme was completely saturated during an experiment? By increasing the substrate concentration. 2. List three conditions that would alter the activity of an enzyme. Be specific with your explanation. Temperature, pH, and concentration can alter the activity of an enzyme. 3. Take a look around your house and identify household products that work by means of an enzyme. Name the products and indicate how you know they work with an enzyme. Dish soap, because warm water causes enzymes to attack stains, breaking the chains of protein and starch down into smaller parts.

EXPERIMENT 1: ENZYMES IN FOOD Data Tables Table 1: Substance vs. Starch Presence Resulting Color (where sample was applied) a dull purple

None

None

A dull purple

None

None

Saliva

White

Yes

Yes

Tomato

White

Yes

Yes

Potato

White

Yes

Yes

Substance Negative Control: Starch Control

Presence of Starch?

Presence of Amylase?

Post-Lab Questions 1. What were your controls for this experiment? What did they demonstrate? Why was saliva included in this experiment? The controls were the starch paper towel and the paper towel with nothing on it, they demonstrated what the paper towel would look like without anything else added to it. saliva was most likely included because it has a lot of Amylase in it. 2. What is the function of amylase? What does amylase do to starch? Amylase helps digestion in humans, amylase breaks down starch. 3. Which of the foods that you tested contained amylase? Which did not? What experimental evidence supports your claim? They both did because they both turned white. 4. Saliva does not contain amylase until babies are two months old. How could this affect an infant’s digestive requirements? They wouldn't be able to properly digest starch.

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5. There is another digestive enzyme (other than salivary amylase) that is secreted by the salivary glands. Research to determine what this enzyme is called. What substrate does it act on? Where in the body does it become activated and why? Lingual lipase, which breaks down fats, is found in the stomach. 6. Digestive enzymes in the gut include proteases, which digest proteins. Why don’t these enzymes digest the stomach and small intestine, which are partially composed of protein? Because of the lining of mucus in the stomach and small intestine.

EXPERIMENT 2: EFFECT OF TEMPERATURE ON ENZYME ACTIVITY Result Tables Table 2: Balloon Circumference vs. Temperature Tube

Temperature (°C)

Balloon Circumference (Uninflated; cm)

Balloon Circumference (1 minute; cm)

Balloon Circumference (3 minutes; cm)

1 – Room Temperature

21

9

15

18

2 – Hot

59

9

14

19

3 – Cold

10

9

19

18.5

Post-Lab Questions 1. What reaction is being catalyzed in this experiment? The reaction between yeast and hydrogen peroxide. 2. What is the enzyme in this experiment? What is the substrate? The enzyme is the yeast and the substrate is the hydrogen peroxide. 3. What is the independent variable in this experiment? What is the dependent variable? The room temperature hydrogen peroxide, the hot and cold temperature of the hydrogen peroxide 4. How does the temperature affect enzyme function? Use evidence from your data to support your answer. Cold Temperature increases the rate of reaction, while hot temperature remains the same. 5. Draw a graph of balloon diameter vs. temperature. What is the correlation?

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6. Is there a negative control in this experiment? If yes, identify the control. If no, suggest how you could revise the experiment to include a negative control. No, a negative control for this would be to test room temperature water. 7. In general, how would an increase in substrate alter enzyme activity? Draw a graph to illustrate this relationship.

The reaction time would increase. 8. Design an experiment to determine the optimal temperature for enzyme function, complete with controls. Where would you find the enzymes for this experiment? What substrate would you use? I would use a catalyst or milk to find the catalase of lactose, and use hydrogen peroxide to find the lactose in lactase. © eScience Labs, 2018

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