0610 Biology November 2025 Question Paper 62

1 A student investigated the rate of respiration in yeast using different concentrations of glucose.

They used a 5% glucose solution to make a 1% glucose solution and a 4% glucose solution.

The student used this method:

Step 1 Label two small test‑tubes 1% and 4%.

Step 2 Use a syringe to put 1 cm3 of 5% glucose solution into the small test‑tube labelled 1%.

Put 4 cm3 of 5% glucose solution into the small test‑tube labelled 4%.

Step 3 Use a clean syringe to put 4 cm3 of distilled water into the small test‑tube labelled 1%.

Put 1 cm3 of distilled water into the small test‑tube labelled 4%.

Step 4 Pour yeast suspension into the small test‑tube labelled 1% until it is completely full.

Step 5 Keep the small test‑tube upright and carefully place a large test‑tube over the top of the small test‑tube labelled 1%. Push the small test‑tube up to the top of the large test‑tube, as shown in Fig. 1.1A. Quickly invert the test‑tubes, as shown in Fig. 1.1B. finger holding the small test-tube in position while the test-tubes are inverted B C A water-bath containing warm water large test-tube small test-tube containing yeast suspension and glucose solution Fig. 1.1

Step 6 Put the large test‑tube and the small test‑tube labelled 1% into a warm water‑bath, as shown in Fig. 1.1C.

Step 7 Start the stop‑clock and wait for five minutes. , ,

Step 8 After five minutes, stop the stop‑clock and use a ruler to measure the height of the yeast suspension in the large test‑tube, as shown in Fig. 1.2. height of the yeast suspension in the large test-tube after five minutes Fig. 1.2

Step 9 Remove the test‑tubes from the warm water‑bath and discard them.

Step 10 Pour yeast suspension into the small test‑tube labelled 4% until it is completely full.

Step 11 Repeat steps 5 to 8 with the small test‑tube labelled 4%. , ,

(a) Fig. 1.3 is a diagram of the water‑baths in steps 8 and 11. 1% glucose solution 4% glucose solution large test-tube Fig. 1.3

(i) Measure the height of the yeast suspension in each of the large test‑tubes shown in Fig. 1.3.

Prepare a table for the results and record your measurements from Fig. 1.3.

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(ii) State a conclusion for the results of this investigation [1]

(iii) State the independent and dependent variables in this investigation. independent variable dependent variable [2]

(iv) Describe how the temperature of the water‑bath could be maintained [1]

(v) Explain why a clean syringe was used in step 3 [1] , ,

(b) A student extended the investigation by using more concentrations of glucose solution.

Calculate the volumes of 5% glucose solution and distilled water that are needed to make 5 cm3 of a 3% glucose solution.

volume of 5% glucose solution cm3

volume of distilled water cm3

[1]

(c) Sports drinks often contain glucose, which is a reducing sugar.

State how you could test a sample of a sports drink for reducing sugar [2]

(d) (i) The ethanol emulsion test can be used to show that a sample of food contains fat.

State the result of a positive test [1]

(ii) Suggest one safety precaution that should be followed when using ethanol [1]

[Total: 14] , ,

2 Plan an investigation to determine the effect of exercise intensity on heart rate in humans [6] , ,

3 (a) Fig. 3.1 is a photograph of a necklace starfish, Fromia monilis. P Q magnification ×0.32 Fig. 3.1

(i) Draw a large diagram of the necklace starfish shown in Fig. 3.1.

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(ii) Line PQ in Fig. 3.1 represents the diameter of the necklace starfish.

Measure the length of line PQ in Fig. 3.1. length of line PQ mm

Calculate the actual diameter of the necklace starfish using the formula and your measurement. magnification = length of line PQ in Fig. 3.1 actual diameter of the necklace starfish

Give your answer to two significant figures.

Space for working mm

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(iii) Fig. 3.2 is a photograph of a spiny starfish, Marthasterias glacialis. Fig. 3.3 is a photograph of a necklace starfish.

The magnifications of the photographs are not the same. spiny starfish necklace starfish

Fig. 3.2

Fig. 3.3

State two ways the spiny starfish in Fig. 3.2 differs from the necklace starfish in Fig. 3.3, and one way it is similar.

Do not include references to size in your answer. difference 1 difference 2 similarity 1 [3] , ,

(b) Seven‑armed starfish live in the sea.

Scientists investigated the distribution of seven‑armed starfish, Luidia ciliaris, in one region. • Photographs of 20 m2 areas of seabed were taken at different depths. • The depth of the water in each area was measured when the water was at its highest level (high tide). • The numbers of seven‑armed starfish in each photograph were counted. • All photographs were taken on the same day in July.

(i) State two ways that the method used by the scientists ensured that the numbers of seven‑armed starfish counted at different depths could be compared. 1 2 [2]

The results of the investigation are shown in Table 3.1. , , Table 3.1 depth / m number of seven‑armed starfish counted 0.0–9.9 337 10.0–19.9 1486 20.0–29.9 1243 30.0–39.9 241 40.0–49.9 121

(ii) Plot a histogram on the grid of the data in Table 3.1.

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(iii) State the depth range in Table 3.1 at which most seven‑armed starfish were found m [1]

(iv) Using the information in Table 3.1, calculate the total number of seven‑armed starfish that were photographed at all depths, and use this value to calculate the percentage of starfish that were photographed in the 0.0–9.9 m range.

Express the percentage as a whole number.

Space for working.

total number of seven‑armed starfish photographed percentage of seven‑armed starfish photographed at 0.0–9.9 m % [3]

[Total: 20] , ,