4.2 Respiration

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Question 7
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A student investigated the effect of glucose concentration on anaerobic respiration in yeast. This is the method used: 1. Add 10 cm3 of yeast and water mixture to each of four measuring cylinders. 2. Add glucose to each cylinder to create concentrations of 0%, 2%, 4%, and 6%. 3. Place the cylinders in a water bath at 30∘C30^\circ\text{C}30∘C for 15 minutes. 4. Record the total volume of liquid mixture and foam in each cylinder. The diagram below shows the measuring cylinders at the end of the investigation: Four measuring cylinders labeled 0%, 2%, 4%, and 6% glucose. Each cylinder has a capacity of 50 cm^3 with graduation marks every 1 cm^3 and labeled numbers every 10 cm^3. At the bottom of each cylinder, there is a dark grey zone representing the yeast mixture, which reaches the 10 cm^3 mark. Above this, a light grey zone represents the foam. In the 0% cylinder, there is no foam, so the top level is at 10 cm^3. In the 2% cylinder, the foam reaches the 25 cm^3 mark. In the 4% cylinder, the top of the foam is at Y, which is 6 small markings above 30 (the 36 cm^3 mark). In the 6% cylinder, the top of the foam is at 2 small markings above 40 (the 42 cm^3 mark). The table below shows the results: | Glucose concentration | Total volume in cm3\text{cm}^3cm3 | | :--- | :--- | | 0% | 10 | | 2% | 25 | | 4% | YYY | | 6% | 42 |

a.

Find the value of Y Y\,Y from the diagram.

[1]
b.

Calculate the volume of foam produced in the cylinder with 4% glucose.

[2]

4.2 Respiration Questions

  1. GCSE
  2. /Biology
  3. /4.2 Respiration