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Lactase is an enzyme that breaks down lactose into glucose and galactose - Edexcel - GCSE Biology - Question 6 - 2019 - Paper 1
Question 6
Lactase is an enzyme that breaks down lactose into glucose and galactose. A student made some alginate beads containing lactase. The student added 10 beads to 20 cm²... show full transcript
Worked Solution & Example Answer:Lactase is an enzyme that breaks down lactose into glucose and galactose - Edexcel - GCSE Biology - Question 6 - 2019 - Paper 1
Step 1
What is the rate of reaction for 25 beads?
Answer
To determine the rate of reaction for the 25 beads, we can use the formula:
For 25 beads, the time taken to produce glucose is 120 seconds. Thus,
Rounding to two decimal places, the rate of reaction is approximately 0.21 s⁻¹. Therefore, the correct answer is C 0.21 s⁻¹.
Step 2
Explain the conclusion that can be made from these results.
Answer
From the results, we observe that as the number of beads containing lactase increases, the time taken to produce glucose decreases. This indicates that an increase in the amount of enzyme present facilitates a faster reaction rate. This suggests that there is a positive correlation between the amount of enzyme (in this case, lactase) and the rate of reaction up to a certain point. Beyond this, factors such as substrate limitation may affect the reaction.
Step 3
Explain why the same volume of lactose solution was used for each test.
Answer
Using the same volume of lactose solution ensures consistency across all tests. This is essential to maintain fair conditions and minimize variables that could affect the outcome of the experiment. Equalizing the volume helps to ensure that any differences in glucose production observed in the results are solely attributed to the variations in the number of beads of lactase used, rather than differences in substrate concentration.
Step 4
Devise a method to find the optimum temperature for the enzyme lactase.
Answer
To find the optimum temperature for the enzyme lactase, follow these steps:
- Set up the equipment: Prepare a water bath set to various temperatures (e.g., 20°C, 30°C, 40°C, 50°C, and 60°C).
- Prepare a standardized lactose solution: Use a consistent concentration of lactose for each test.
- Add a fixed number of lactase beads: Ensure to keep the number of beads constant across all temperature tests.
- Measure the reaction: Place the lactase beads into the lactose solution at the specified temperature for a fixed duration, then measure the amount of glucose produced.
- Record Results: Repeat the experiment for each temperature and record the time taken for glucose production.
- Analyze Data: Compare the amount of glucose produced at each temperature to determine which temperature yields the highest reaction rate, indicating the optimum temperature for lactase activity.