IGCSE Biology 0610/53 May/June 2025 Past Paper with Answers

Question 1

A student measures the height of foam (in mm) produced when potato catalase breaks down hydrogen peroxide at three temperatures: cold (test-tube C), room temperature (test-tube R) and hot (test-tube H). Which option describes a correct results table and the expected pattern of the results?

1. a table with at least two ruled columns and a header line, with headings and units such as test-tube and height of foam in mm, recording a foam height for C, R and H, with the cold test-tube C giving a lower foam height than the room-temperature test-tube R
2. a table with columns headed test-tube and height of foam but with no units given anywhere, recording a value for each of the three test-tubes
3. a table that records only the foam height for test-tube R, leaving test-tubes C and H blank so the three temperatures cannot be compared
4. a table with correct headings and units but showing the cold test-tube C giving a higher foam height than the room-temperature test-tube R

Question 2

In the investigation the cold test-tube C produced the least foam and the warmer test-tubes produced more foam, showing that more oxygen was released from the breakdown of hydrogen peroxide by catalase. What is the correct conclusion about the effect of temperature on the activity of catalase?

1. increasing the temperature increases the activity of catalase, so more foam is produced
2. increasing the temperature decreases the activity of catalase, so less foam is produced
3. the temperature has no effect on the activity of catalase
4. catalase only works at cold temperatures and stops working when it is warmer

Question 3

In this investigation the student places the test-tubes at different temperatures and measures the height of the foam produced by the catalase reaction. What are the independent and dependent variables?

1. independent variable: the temperature; dependent variable: the height of the foam
2. independent variable: the height of the foam; dependent variable: the temperature
3. independent variable: the volume of hydrogen peroxide; dependent variable: the temperature
4. independent variable: the time left in the water-bath; dependent variable: the volume of potato extract

Question 4 · Answer A

Step 1: The investigation tests the effect of temperature, so the contents must be at the water-bath temperature before the reaction begins. Step 2: Leaving the tubes for five minutes lets the hydrogen peroxide warm up or cool down to match the water-bath. Step 3: This means the reaction happens at the intended temperature, making the test fair.

Question 5 · Answer A

Step 1: Repeating the investigation produces several readings for each temperature. Step 2: Any reading that does not fit the pattern can be spotted as an anomaly and ignored. Step 3: Using the remaining consistent readings (and their mean) makes the results more reliable.

Question 6 · Answer A

Step 1: The hazards are the sharp knife and the grinding action of the pestle. Step 2: Cutting on a tile with the blade moving away from the body keeps the knife away from the hands. Step 3: Keeping the fingers out of the mortar while grinding stops them being crushed by the pestle.

Question 7 · Answer A

Step 1: The foam is a cylinder, so volume = π × r² × h, and the radius is half the diameter: r = 25 ÷ 2 = 12.5 mm. Step 2: Volume = 3.14 × 12.5² × 29 = 3.14 × 156.25 × 29 = 14228.125 mm³. Step 3: Convert to cm³ by dividing by 1000: 14228.125 ÷ 1000 = 14.228… = 14.2 cm³ to one decimal place.

Question 8 · Answer A

Step 1: Foam height only indirectly indicates the gas, so a method that captures the gas itself is better. Step 2: A gas syringe (or an upturned measuring cylinder over water) collects the oxygen and gives a direct volume reading. Step 3: This measures the volume of oxygen accurately, unlike estimating from the foam.

Question 9 · Answer A

Step 1: Iodine solution is the test for starch. Step 2: When starch is present, the orange-brown iodine turns blue-black. Step 3: So a blue-black colour is a positive result for starch.

Question 10 · Answer A

Step 1: Vitamin C is detected using DCPIP, a blue dye. Step 2: When vitamin C is added, it decolourises the blue DCPIP. Step 3: So DCPIP is the reagent used to test for vitamin C.

Question 11 · Answer A

Step 1: Light intensity is the independent variable, so it must be changed over several values, for example by altering the lamp distance. Step 2: The rate of photosynthesis is measured as the volume of oxygen produced in a fixed time, the dependent variable. Step 3: The temperature, plant species and carbon dioxide concentration are kept constant and the readings repeated; only the first plan does all of this.

Question 12 · Answer A

Step 1: A biological drawing uses single, clear, continuous lines with no shading or colouring. Step 2: It should be large, filling much of the available space. Step 3: It must show the observed structures, here the textured point at the tip of the nut and the shape of the cupule with its stalk.

Question 13 · Answer A

Step 1: Rearrange magnification = length of PQ ÷ actual length to give actual length = length of PQ ÷ magnification. Step 2: Actual length = 84 ÷ 3.4 = 24.7… mm. Step 3: To two significant figures this is 25 mm.

Question 14 · Answer A

Step 1: A valid difference is a visible feature that is not the same in both acorns. Step 2: The Turkey oak acorn has a flatter nut top, while the Caucasian oak has a rounded one. Step 3: The Turkey oak cupule has spines, while the Caucasian oak cupule is smooth, giving two correct differences.

Question 15 · Answer A

Step 1: A factor kept constant is one that is the same for every pot. Step 2: All the acorns were grown in the same type of soil and at the same temperature of 25 °C. Step 3: So the type of soil and the temperature are two controlled factors.

Question 16 · Answer A

Step 1: Both axes are labelled with units and a suitable, even scale is chosen so the bars fill more than half the grid. Step 2: All six bars (mean mass and proportion germinated for each of the three species) are plotted accurately with gaps between the species. Step 3: A key identifies which bars show the mean mass and which show the proportion germinated.

Question 17 · Answer A

Step 1: Individual acorns vary, so a few might not represent the species. Step 2: Measuring 100 acorns gives a large, representative sample. Step 3: This reduces the effect of variation between individuals and avoids bias, so the trend is more reliable.

Question 18 · Answer A

Step 1: Water lost = initial mass − dried mass = 1.96 − 0.74 = 1.22 g. Step 2: Percentage water content = (water lost ÷ initial mass) × 100 = (1.22 ÷ 1.96) × 100. Step 3: This gives 62.24… = 62.2 %.

Question 19 · Answer A

Step 1: Protein is detected using biuret solution. Step 2: When protein is present, the blue biuret solution turns purple (lilac). Step 3: So biuret solution is the reagent used to test for protein.