Lab 14 Enzyme activity experiment

Summary

This video explains a laboratory experiment focused on enzyme reactions, specifically the breakdown of hydrogen peroxide by catalase found in bananas. The experiment explores the effects of pH, temperature, and substrate concentration on enzyme activity. The process involves controlling variables such as banana size, test tubes, and liquid amounts while measuring the resulting bubbling as an indicator of enzyme activity. Results show how different pH levels, temperatures, and hydrogen peroxide concentrations impact the rate of catalase activity, emphasizing the role of heat and substrate concentration in accelerating reactions.

Takeaways

• 😀 The enzyme catalase in banana breaks down hydrogen peroxide into bubbles, indicating enzyme activity.
• 😀 The experiment starts by testing the effect of pH on enzyme activity using three different solutions: water, hydrochloric acid (HCl), and sodium hydroxide (NaOH).
• 😀 Different pH levels (6-7 for water, 1 for acid, and 12-13 for base) are tested to observe enzyme activity through bubble formation.
• 😀 The presence of bubbles signifies active enzyme catalysis, with the highest bubble formation observed in the water (neutral pH) test tube.
• 😀 In the temperature experiment, enzyme activity is observed at room temperature, ice-cold water, and boiling water to study temperature effects.
• 😀 The enzyme in the banana is tested at various temperatures to observe its reaction to freezing and heating, with the cold water significantly reducing activity and boiling water stopping it altogether.
• 😀 Heat generally speeds up reactions, but in this experiment, the enzyme's activity is hindered at high temperatures, which leads to fewer bubbles or no reaction.
• 😀 The experiment also explores the effect of substrate concentration on enzyme activity using different concentrations of hydrogen peroxide (3%, 1%, and 0.03%).
• 😀 A higher substrate concentration results in more bubbles and faster breakdown of hydrogen peroxide, indicating increased enzyme activity.
• 😀 The visual difference in bubble formation between the different concentrations shows a direct relationship between substrate concentration and enzyme activity.
• 😀 The experiments are qualitative, with a focus on observing and comparing bubbling at different pH levels, temperatures, and substrate concentrations.
• 😀 The video concludes by showing time-lapse results of the experiments, with a reminder to clean up and appreciate the role of enzymes in breaking down hydrogen peroxide.

Q & A

What enzyme is involved in the reaction observed in the experiment?

The enzyme involved in the experiment is catalase, which breaks down hydrogen peroxide into oxygen and water, producing bubbles.

What indicates that the enzyme catalase is active during the experiment?

The presence of bubbles indicates that the enzyme catalase is active, as it is breaking down hydrogen peroxide into oxygen.

How is the effect of pH on enzyme activity tested in the experiment?

The effect of pH on enzyme activity is tested by placing banana samples in test tubes with different pH solutions (acidic, neutral, and basic) and adding hydrogen peroxide. The reaction is observed by looking for bubbles.

What pH levels are tested in the experiment, and how are they measured?

The pH levels tested are approximately 6-7 (neutral water), around 1 (acidic, using hydrochloric acid), and around 12-13 (basic, using sodium hydroxide). The pH is measured using pH paper.

How does temperature affect enzyme activity in this experiment?

Temperature affects enzyme activity by altering the rate of the reaction. Room temperature, ice water (cold), and boiling water (hot) are tested, with different levels of enzyme activity observed based on temperature.

What results were observed when the enzyme catalase was exposed to cold temperatures?

When the enzyme was exposed to cold temperatures (ice water), very few bubbles were observed, indicating that enzyme activity was reduced or slowed down due to the cold.

What was the effect of hot water on enzyme activity in the experiment?

In the hot water test, there was little or no bubbling, which suggests that the heat denatured the catalase enzyme, rendering it inactive or less effective.

How is the concentration of hydrogen peroxide varied in the experiment, and why?

The concentration of hydrogen peroxide is varied by adding different amounts to the test tubes: 3% peroxide in the first, 1% in the second, and 0.03% in the third. This tests the effect of substrate concentration on enzyme activity.

What is the observed result of varying hydrogen peroxide concentration on the reaction?

The reaction rate increases with higher hydrogen peroxide concentration. The highest concentration (3%) produced the most bubbles, while the lowest concentration (0.03%) produced almost no bubbles.

Why does the experiment use banana samples for testing catalase activity?

Banana samples are used because they naturally contain the enzyme catalase, which can catalyze the breakdown of hydrogen peroxide, making them suitable for testing enzyme activity in the experiment.