4.2 Respiration

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Question 4
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A group of students investigated the effect of sucrose concentration on anaerobic respiration in yeast. They used the following method:

  1. Add 15 cm3 of yeast and nutrient broth mixture to each of four 100 cm3 measuring cylinders.
  2. Add sucrose to each cylinder to produce concentrations of 0%, 1.5%, 3.0%, and 4.5%.
  3. Place the cylinders in a water bath at 35∘C35^\circ\text{C}35∘C for 20 minutes.
  4. Record the total volume of the mixture and foam in each cylinder.

The diagram below shows the measuring cylinders at the end of the investigation:

Four measuring cylinders containing yeast mixture and foam at concentrations of 0%, 1.5%, 3.0%, and 4.5% sucrose.

The table below shows the results:

Sucrose concentrationTotal volume / cm3\text{cm}^3cm3
0%15
1.5%38
3.0%ZZZ
4.5%72
a.

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

[1]
b.

Calculate the volume of foam produced in the cylinder with 3.0% sucrose.

[2]

4.2 Respiration Questions

  1. GCSE
  2. /Biology
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