UMUC Biology 102/103
Lab 4: Enzymes
INSTRUCTIONS:
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Experiment 1: Enzymes in Food (15 pts)
Table 1: Substance vs. Starch Presence
Substance Resulting Color Presence of Starch?
Positive Control: Starch
Negative Control: Student Must Select
Food Product:
Food Product:
Saliva:
Post-Lab Questions
1. What were your controls for this experiment? What did they demonstrate? Why was saliva included in this experiment?
2. What is the function of amylase? What does amylase do to starch?
3. Which of the foods that you tested contained amylase? Which did not? What experimental evidence supports your claim?
4. Saliva does not contain amylase until babies are two months old. How could this affect an infant’s digestive requirements?
5. 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 (15 pts)
Table 2: Record the effect of temperature on the production of gas
Tube Temperature
(°C) Balloon Circumference
(Uninflated in cm)
Balloon Circumference
(Inflated in cm)
1 (cold)
2 (room temp)
3 (hot)
Post-Lab Questions
1. What is the enzyme in this experiment? What is the substrate?
2. What is the independent (IV) and dependent (DV) variables in this study?
3. How does temperature affect enzyme function?
4. How can enzyme activity be increased?
5. In general, how would an increase in substrate alter enzyme activity? Draw or insert a graph to illustrate this relationship.
6. Draw a graph using balloon diameter vs. temperature. You may use Excel, then “Insert” the graph, or use another drawing program. You may also draw it neatly by hand and scan your drawing. You would need to insert the scanned jpg image here, in that case. What is the correlation shown on your graph?
7. Design an experiment to determine the optimal temperature for enzyme function, complete with controls. Be sure to state your hypothesis, describe your design, dissect your variables (IV/DV), and predict your results. When you describe your design, be sure to explain where you will find the enzymes for this experiment and what substrate you will use.