Answer the following in relation to enzymes - Leaving Cert Biology - Question 9 - 2012
Question 9
Answer the following in relation to enzymes.
(i) What is their chemical nature?
(ii) Comment upon their molecular shape.
(b) Answer the following in relation to a... show full transcript
Worked Solution & Example Answer:Answer the following in relation to enzymes - Leaving Cert Biology - Question 9 - 2012
Step 1
What is their chemical nature?
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Answer
Enzymes are biological catalysts that are primarily composed of proteins. They accelerate chemical reactions in biological systems by lowering the activation energy required for the reaction to proceed.
Step 2
Comment upon their molecular shape.
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Answer
Enzymes have a specific three-dimensional structure that is essential for their function. This shape allows them to have an active site that is complementary to the substrate, enabling the formation of enzyme-substrate complexes.
Step 3
Name the enzyme that you used.
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Answer
The enzyme used was catalase.
Step 4
Name the substrate of this enzyme.
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Answer
The substrate for catalase is hydrogen peroxide (H2O2).
Step 5
Why was it necessary to keep the pH constant in the course of the investigation?
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Maintaining a constant pH is necessary to eliminate it as a variable that could influence the reaction rate. Enzymes have an optimal pH at which they function best, and significant deviations can lead to denaturation or reduced activity.
Step 6
How did you keep the pH constant?
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I used a buffer solution to maintain the pH at a stable level throughout the experiment.
Step 7
How did you vary the temperature in the course of the investigation?
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I varied the temperature by placing the enzyme and substrate solutions in water baths set to different temperatures.
Step 8
How did you know that the enzyme was working?
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I observed the release of oxygen gas as visible bubbles when hydrogen peroxide was broken down by catalase, indicating that the enzyme was active.
Step 9
Use the axes below to summarise the results of your investigation. Do this by labelling the axes.
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The x-axis represents Temperature (°C), and the y-axis represents the Rate of Reaction (measured in mL of O2 produced).
The graph should show a bell-shaped curve indicating that enzyme activity increases with temperature to a certain point, after which it declines due to denaturation.
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