UMUC Biology 102/103

Lab 4: Enzymes

 INSTRUCTIONS:

 

 

 ·         On your own and without assistance, complete this Lab 4 Answer Sheet electronically and submit it via the Assignments Folder by the date listed in the Course Schedule (under Syllabus ).

 ·         To conduct your laboratory exercises, use the Laboratory Manual located under Course Content. Read the introduction and the directions for each exercise/experiment carefully before completing the exercises/experiments and answering the questions.

 ·         Save your Lab 4 Answer Sheet in the following format:  LastName_Lab4 (e.g., Smith_Lab4) .

 ·         You should submit your document as a Word (.doc or .docx) or Rich Text Format (.rtf) file for best compatibility.

 

 

 

 

 

Pre-Lab Questions

 

 

 How could you test to see if an enzyme was completely saturated during an experiment?

 

 

 

 

 List three conditions that would alter the activity of an enzyme. Be specific with your explanation.

 

 

 

 

 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.

 

 

 

 

 

 

 

Experiment 1: Enzymes in Food

 

 

 

 

 

Data Tables and Post-Lab Assessment

 

Table 1: Substance vs. Starch Presence

 

Table 1: Substance vs. Starch Presence

Substance

Resulting Color

Presence of Starch?

Positive Control: Ginger Root

 

 

Negative Control: Student Must Select

 

 

Food Product:

 

 

Food Product:

 

 

Saliva:

 

 

 

 

 

Post-Lab Questions

 

What were your controls for this experiment? What did they demonstrate? Why was saliva included in this experiment?

 

 

 

What is the function of amylase? What does amylase do to starch?

 

 

 Which of the foods that you tested contained amylase? Which did not? What experimental evidence supports your claim?

 

 

  Saliva does not contain amylase until babies are two months old. How could this affect an infant’s digestive requirements?

 

 

 

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?

 

 

 

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?

 

 

 

 

 

Experiment 2: Effect of Temperature on Enzyme Activity

 

 

 

Data Tables and Post-Lab Assessment

 

Table 2: Balloon Circumference vs. Temperature

 

 

 

Table 2: Balloon Circumference vs. Temperature

Tube

Temperature (°C)

Uninflated Balloon Circumference (cm)

Final Balloon Circumference (cm)

Difference in Balloon Circumference (cm)

1 – (Cold)

 

 

 

 

2 – (RT)

 

 

 

3 – (Hot)

 

 

 

 

 

 

 

 

Post-Lab Questions

 What reaction is being catalyzed in this experiment?

  What is the enzyme in this experiment? What is the substrate?

  What is the independent variable in this experiment? What is the dependent variable?

  How does the temperature affect enzyme function? Use evidence from your data to support your answer.

  Draw a graph of balloon diameter vs. temperature. What is the correlation?

  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.

  In general, how would an increase in substrate alter enzyme activity? Draw a graph to illustrate this relationship.

 

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?