Exercise 1: Enzymes and Temperature

QUESTIONS

A. Which color indicated that starch was still present in the test tube? Which color indicated that the starch was no longer present?

B. When the starch "disappeared" as indicated by the color change, what happened to it?

C. What is the variable in this exercise?

What could be considered the control treatment?

D. Based on the results recorded in Data Table 1, which temperature(s) is/are optimal for enzyme conversion activity?

Which temperature facilitated the conversion first? Second?

E. Did other temperatures facilitate enzyme activity at all?

Why or why not?

F. Why was the water bath temperature of 37°C chosen as the "mid-range" temperature? Hint: What is the ºF equivalent of this ºC temperature?

G. Why was it important to immediately observe the color of the test tube contents/iodine in the microplate well?

H. Why didn't you add the iodine indicator directly to the test tubes?

I. What happened when you incubated the test tube(s) that still contained amylase/starch at 37°C?

Did both test tubes indicate the disappearance of starch after the incubation?

J. What happened after you added 1 cm of alpha-amylase solution to the test tube(s) that still contained starch, and incubated them at 37°C?

Why did this occur after the second addition of amylase, but not before?

K. Construct a graph that presents your findings from Table 1 with time on the x-axis, and relative concentration of starch on the y-axis (++ is highest, +, or - is lowest). Include the graph in the report.

DISCUSSION

A. Was the initial hypothesis supported or refuted? Explain.

B. What have you learned from this experiment?

C. What practical applications could this knowledge have?

Exercise 2: Enzymes and Substrate Concentration
QUESTIONS

A. What is the variable in this exercise?

B. Which test tube has the highest concentration of alpha-amylase in the starch?

C. How could this experiment be improved?

D. Construct a graph that presents your findings in Table 2 with time on the x-axis, and relative concentration of starch on the y-axis (++ is highest, +, or - is lowest). Use five different colors to represent the concentration of amylase. Include it in the report.

DISCUSSION

A. Was your initial hypothesis supported or refuted as to which test tube starch contents would convert to sugar first?

B. What have you learned from this experiment?

C. What practical applications could this knowledge have?

D. Describe another way to do this experiment that would test the same concept.

Exercise 3: Enzymes and pH
QUESTIONS

A. What is the variable in this experiment?

B. In which test tube(s) did the amylase convert starch to sugar? Why might you expect this outcome?

C. Did any test tubes NOT exhibit a color change? Why?

DISCUSSION

A. Did the results support or refute your hypothesis as to which test tube starch contents would convert to sugar first?

LABORATORY SUMMARY

A. What other conditions that may affect the action of enzymes?

B. How might you propose to test this?

C. What have you learned from this laboratory?

D. What practical applications might this knowledge have?