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A student investigated the effect of different sugar solutions on potato tissue - AQA - GCSE Biology - Question 5 - 2018 - Paper 1
Question 5
A student investigated the effect of different sugar solutions on potato tissue. This is the method used. 1. Add 30 cm³ of 0.8 mol dm⁻³ sugar solution to a boiling... show full transcript
Worked Solution & Example Answer:A student investigated the effect of different sugar solutions on potato tissue - AQA - GCSE Biology - Question 5 - 2018 - Paper 1
Step 1
0.5 Why did the student calculate the percentage change in mass as well as the change in grams?
Answer
The student calculated the percentage change in mass to allow the results to be compared more effectively. This method accounts for the initial mass differences among potato cylinders, providing a standardized measure of change relative to starting weight.
Step 2
0.5.3 Complete Figure 3 using data from Table 2.
Answer
- Set the x-axis to represent the concentration of sugar solution in mol dm⁻³, ranging from 0 to 0.8.
- Label the y-axis as 'Percentage change in mass (%)', ranging from -15 to +20.
- Plot the points based on final mass changes:
- For 0.2: 0.8%
- For 0.4: 3.8%
- For 0.6: -4.5%
- For 0.8: -9.0%
- Draw a line of best fit that represents the trend of the data accurately.
Step 3
Step 4
0.5.5 Explain why the percentage change results are positive and negative.
Answer
The positive percentage change indicates that water entered the potato cells when exposed to lower concentrations of sugar solution (0.2 and 0.4), resulting in gain in mass. Conversely, the negative percentage change suggests that water exited the potato cells when they were placed in more concentrated solutions (0.6 and 0.8), leading to a loss in mass due to osmosis.
Step 5