Other than those stated, suggest two variables the student needed to keep constant in her investigation. 1 2 Figure 3 shows the result she obtained for yeast in glucose solution. Figure 3 Bubble containing carbon dioxide produced Use Figure 2 and Figure 3 to calculate the rate of carbon dioxide production in mm s⁻¹ for yeast in glucose solution. Give your answer in standard form and to 2 significant figures. Show your working. Answer __________________ mm s⁻¹ The student repeated the experiment using yeast in maltose solution. She found the rate of carbon dioxide production was slower than yeast in glucose solution. Suggest. A second student used a different method to investigate the effect of different sugars on the rate of respiration in yeast. He set up a tube with yeast in glucose solution and added bromothymol blue. Bromothymol blue changes from blue to yellow when carbon dioxide is produced. Suggest: • why the method the second student used would be less accurate than the method the first student used • how the accuracy of the method the second student used could be improved. This method would be less accurate because. Complete the boxes A to D in Figure 4 to show the link reaction. Figure 4

A-Level AQA Biology 5.2 Respiration (A Level only): Other than those stated, suggest

Other than those stated, suggest two variables the student needed to keep constant in her investigation - AQA - A-Level Biology - Question 2 - 2023 - Paper 3

Question 2

Other than those stated, suggest two variables the student needed to keep constant in her investigation. 1 2 Figure 3 shows the result she obtained for yeast in gl... show full transcript

Worked Solution & Example Answer:Other than those stated, suggest two variables the student needed to keep constant in her investigation - AQA - A-Level Biology - Question 2 - 2023 - Paper 3

Step 1

Suggest two variables the student needed to keep constant.

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Answer

Concentration of glucose solution.
Volume of yeast.

Step 2

Use Figure 2 and Figure 3 to calculate the rate of carbon dioxide production in mm s⁻¹ for yeast in glucose solution.

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Answer

To find the rate of carbon dioxide production, we can read the height of the bubble produced in Figure 3 and the time taken from Figure 2. Assuming the bubble height is approximately 36.5 mm and the time taken is 15 seconds:

Rate = ( \frac{Height}{Time} = \frac{36.5 \text{ mm}}{15 \text{ s}} = 2.43 \text{ mm s}^{-1} \approx 2.4 \times 10^0 \text{ mm s}^{-1} )

Step 3

Suggest why the method the second student used would be less accurate than the method the first student used.

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Answer

The method is less accurate because the color change endpoint is subjective and can lead to inconsistencies in timing.

Step 4

Suggest how the accuracy of the method the second student used could be improved.

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Answer

Using a colorimeter to provide a precise quantitative measurement for the color change would improve accuracy.

Step 5

Complete the boxes A to D in Figure 4 to show the link reaction.

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Answer

A: Pyruvate B: Reduced NAD C: Acetyl-CoA D: Carbon dioxide

Other than those stated, suggest two variables the student needed to keep constant in her investigation - AQA - A-Level Biology - Question 2 - 2023 - Paper 3

Worked Solution & Example Answer:Other than those stated, suggest two variables the student needed to keep constant in her investigation - AQA - A-Level Biology - Question 2 - 2023 - Paper 3

Suggest two variables the student needed to keep constant.

Use Figure 2 and Figure 3 to calculate the rate of carbon dioxide production in mm s⁻¹ for yeast in glucose solution.

Suggest why the method the second student used would be less accurate than the method the first student used.

Suggest how the accuracy of the method the second student used could be improved.

Complete the boxes A to D in Figure 4 to show the link reaction.

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