AP Biology Lab 2: Enzyme Catalysis

Summary

In this AP Biology lab on enzyme catalysis, Mr. Andersen explains the role of catalase, an enzyme found in nearly all living organisms that breaks down hydrogen peroxide into water and oxygen. Through a hands-on experiment with yeast and filter paper, students observe how varying enzyme concentrations impact reaction rates. The video also discusses how factors like temperature, pH, and substrate concentration influence enzyme activity. The experiment highlights the vital role enzymes play in speeding up reactions, and the lab results help students understand how enzyme concentration affects the breakdown process of hydrogen peroxide.

Takeaways

• 😀 Catalase is an enzyme found in nearly all living organisms that breaks down hydrogen peroxide into water and oxygen.
• 😀 Enzymes act as catalysts, speeding up chemical reactions without being consumed in the process.
• 😀 The enzyme catalase breaks down hydrogen peroxide (H₂O₂) into water (H₂O) and oxygen (O₂), causing oxygen bubbles to form.
• 😀 The experiment uses yeast as a source of catalase to study enzyme activity in breaking down hydrogen peroxide.
• 😀 The rate of the reaction is measured by timing how long it takes for a piece of filter paper (with catalase) to float in hydrogen peroxide.
• 😀 Higher concentrations of yeast (catalase) result in faster breakdown of hydrogen peroxide and quicker floating of the filter paper.
• 😀 If no yeast is present, the filter paper will not float because there is no catalase to break down the hydrogen peroxide.
• 😀 The rate of enzyme activity increases with more yeast, but eventually, the reaction plateaus due to the depletion of hydrogen peroxide.
• 😀 Temperature, pH, and substrate concentration can all affect the rate of enzyme activity, with each enzyme having an optimal range for these factors.
• 😀 Enzymes are most efficient at an optimal temperature and pH, and excessive heat or incorrect pH can cause enzyme denaturation, reducing effectiveness.
• 😀 In the experiment, the rate of enzyme activity was measured in 'floats per second,' where the number of floats correlates to the reaction speed.

Q & A

What is the main enzyme studied in this lab?

The main enzyme studied in this lab is catalase, which is found in yeast and breaks down hydrogen peroxide into water and oxygen.

What does the enzyme catalase break down?

Catalase breaks down hydrogen peroxide (H2O2) into water (H2O) and oxygen (O2), causing bubbling.

Why do wounds bubble when hydrogen peroxide is applied?

The bubbling occurs because catalase, an enzyme found in many living organisms, breaks down the hydrogen peroxide into water and oxygen.

How is enzyme activity measured in this experiment?

Enzyme activity is measured by timing how long it takes for a filter paper dipped in yeast (containing catalase) to float after being placed in hydrogen peroxide. The rate is calculated in floats per second.

What effect does increasing the concentration of yeast have on the reaction?

Increasing the concentration of yeast (and therefore catalase) speeds up the breakdown of hydrogen peroxide, causing the filter paper to float faster.

What happens when no yeast is present in the reaction?

When no yeast is present, catalase is absent, and the filter paper does not float because hydrogen peroxide is not broken down into oxygen and water.

What is the significance of the 'floats per second' unit?

The 'floats per second' unit measures the rate of the reaction. It represents how quickly the filter paper floats, which correlates with how fast the hydrogen peroxide is being broken down.

How does temperature affect enzyme activity in this experiment?

Temperature increases enzyme activity to a point, as higher temperatures cause molecules to move faster and collide more frequently. However, if the temperature becomes too high, the enzyme can denature and lose its effectiveness.

What is the optimal temperature for enzyme activity in humans?

The optimal temperature for enzyme activity in humans is around 37°C, as it is the normal body temperature where enzymes like catalase work most efficiently.

How does pH influence enzyme activity?

pH affects enzyme activity by altering the enzyme's structure. Enzymes have an optimal pH where they function best. Extreme acidic or basic conditions can denature the enzyme, reducing its effectiveness.