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Pre lab questions with procedure and conclusions of catalase enzyme lab
Typology: Lab Reports
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Introduction: Catalysts are substances that speed up chemical reactions. Organic catalysts are called enzymes. Catalase is an enzyme normally found in many plant and animal tissues. The biological purpose of catalase is to destroy toxic substances that may be introduced into cells. Also, some cells use catalase to destroy cellular debris or worn out organelles. In this lab, we will use a catalase solution from potatoes and determine the effect of temperature and pH on the action of this enzyme. The substrate of the enzyme will be 3% hydrogen peroxide (H 2 O 2 ). Catalase works by the following mechanism:
2 H 2 O 2 --------->2 H 2 O + O 2
The development of oxygen gas can be observed by the foam produced in a test tube.
Materials:
Eye protection Metric ruler Red-skinned potatoes Test tube rack Scalpel or knife (for cutting and mashing the potato) Marker pen or pencil H 2 O 2 Test tube clamps Test tubes acid (HCl) Hot water bath base (NaOH) Ice bath Rocks or pebbles pH paper
CAUTION! HCl and NaOH are strong acids and bases. If you spill these chemicals on your skin, immediately wash in running water. Wear eye protection at all times. Be careful of hot water and hot plates.
Pre Lab Questions (Need help? Use pg. 57 in the Modern Biology text)
a) Active site:
b) Substrate:
c) Denature:
Part A: Exploring Catalase Activity
Procedure :
Observe the reactions in the 4 tubes for 5 minutes. Note how vigorously each reaction โbubblesโ (emits oxygen gas) in Table 1. Using a metric ruler, measure the height of the bubbles produced after 5 minutes.
Part A: Results and Observations: After adding the H 2 O 2 , watch the clock and record activity based on oxygen bubbles (product) given off. Rate the activity for each test tube using the following rating scale and complete Table 1 with these symbols:
Table 1: Activity of Enzyme on Hydrogen Substrate Decomposition tube Test tube First minute activity rating
5 minute activity rating
Height of bubbles (cm)
Scientific explanation
1 Pebble in H 2 O 2
2 Potato cube and H 2 O 2 3 Chopped potato and H 2 O 2 4 Chopped potato and water
Part B
Data:
Table 2: Effect of Temperature on Catalase Reactions Test tube Temperature (oC) Height of Bubbles (cm)
Hot
Room Temp
Cold
Part C: The Effect of pH on Enzyme Activity:
Table 3: Effect of pH on Catalase Reactions
pH
Height of Bubbles (cm)
Comments:
Acid
Neutral
Base
Analysis and Conclusions: