IGCSE Biology 0610/52 May/June 2025 Past Paper with Answers

Question 1

A student needs to make 50 cm³ of a 0.5 mol per dm³ salt solution by mixing 1.0 mol per dm³ salt solution S with distilled water W. Which volumes of S and W should be used?

1. 25 cm³ of salt solution S and 25 cm³ of distilled water W
2. 50 cm³ of salt solution S and 0 cm³ of distilled water W
3. 10 cm³ of salt solution S and 40 cm³ of distilled water W
4. 5 cm³ of salt solution S and 45 cm³ of distilled water W

Question 2

A student measures the total length of 10 potato discs before and after leaving them for 20 minutes in salt solutions of 1.0, 0.5 and 0.0 mol per dm³. Which option describes a correct results table and the expected pattern of the results?

1. a table with at least three ruled columns and headings with units (concentration in mol per dm³, length in mm), recording the initial and final length for each of the three concentrations, with the greatest change in length in the 1.0 mol per dm³ solution
2. a table with columns headed concentration and length but with no units given anywhere, recording the initial and the final lengths for each of the three concentrations
3. a table that records only the final length of the discs in each solution, with no initial lengths and therefore no way to work out the change in length
4. a table with the correct headings and units but showing the greatest change in length in the 0.0 mol per dm³ solution and the smallest change in the 1.0 mol per dm³ solution

Question 3

The total length of the 10 potato discs was 30 mm in each beaker at the start. After 20 minutes the lengths were 26 mm in S1 (1.0 mol per dm³), 29 mm in S2 (0.5 mol per dm³) and 33 mm in S3 (0.0 mol per dm³). What is the change in total length in each beaker?

1. S1 −4 mm, S2 −1 mm, S3 +3 mm
2. S1 +4 mm, S2 +1 mm, S3 −3 mm
3. S1 26 mm, S2 29 mm, S3 33 mm
4. S1 4 mm, S2 1 mm, S3 3 mm

Question 4 · Answer A

Step 1: A decrease in length means the discs lost water by osmosis. Step 2: The discs in the most concentrated salt solution lost the most length, so they lost the most water. Step 3: In distilled water the discs gained water and grew, so higher salt concentration means more water leaves the discs.

Question 5 · Answer A

Step 1: The dependent variable is the quantity that is measured in response to the change. Step 2: Here the student measures the total length of the potato discs. Step 3: So the length of the discs is the dependent variable.

Question 6 · Answer A

Step 1: A source of error is a feature of the method that makes the measurement less accurate. Step 2: The discs are curved and hard to line up perfectly, so the total length read off the ruler is uncertain. Step 3: The other options are correct, careful parts of the method, not errors.

Question 7 · Answer A

Step 1: Cutting safely means controlling the blade so it cannot slip onto the body. Step 2: Cutting on a flat tile with the blade moving away from the hand keeps fingers clear of the blade. Step 3: The other options put the hand or body in the path of the blade or do not address the cutting hazard.

Question 8 · Answer A

Step 1: Iodine solution is the test for starch. Step 2: When starch is present, orange-brown iodine turns blue-black. Step 3: Potato cells store starch, so the iodine turns blue-black, showing starch is present.

Question 9 · Answer A

Step 1: A biological drawing uses single, clear, continuous lines with no shading or colouring. Step 2: It should be large, using at least half of the available space. Step 3: It must show the observed structures, here the stalk, the midrib (drawn as a double line) and the bumps near the base of the leaf.

Question 10 · Answer A

Step 1: Magnification = length in the picture ÷ actual length = 63 ÷ 39. Step 2: 63 ÷ 39 = 1.615…. Step 3: To two significant figures this is 1.6.

Question 11 · Answer A

Step 1: A valid difference must be a visible feature, other than size, that is not the same in both leaves: the potato edge is smooth while the tomato edge is lobed. Step 2: A valid similarity is a feature shared by both, such as a central midrib. Step 3: Only the first option pairs a true difference with a true similarity.

Question 12 · Answer A

Step 1: A constant temperature needs a controlled heat source that holds one set value. Step 2: A thermostatically controlled water-bath set to 40 °C keeps the mixture steadily at that temperature. Step 3: The bench, a Bunsen burner and a fridge all give the wrong or a changing temperature.

Question 13 · Answer A

Step 1: A fair test keeps everything constant except the variable being investigated, which here is the pectinase concentration. Step 2: Each run must use the same mass of crushed apple and the same volume of pectinase solution. Step 3: So the mass of apple and the volume of pectinase are the variables kept constant.

Question 14 · Answer A

Step 1: Both axes are labelled with their units and a linear (evenly spaced) scale is chosen so the plotted points fill more than half of the grid. Step 2: Every point is plotted accurately. Step 3: A single suitable line is then drawn through the points.

Question 15 · Answer A

Step 1: A concentration of 0.5% lies between the 0.4% result (12 cm³) and the 0.8% result (22 cm³). Step 2: It is just above 0.4%, so the volume is a little above 12 cm³. Step 3: Reading between the points gives an estimate of about 15 cm³.

Question 16 · Answer A

Step 1: From 0.1% to 0.8% the volume rises, so more enzyme produces more juice. Step 2: From 0.8% to 1.6% the volume stays at 22 cm³, so it has levelled off. Step 3: So the volume increases with concentration and then levels off.

Question 17 · Answer A

Step 1: The optimum is the concentration giving the most juice, and the present data jump from 0.4% to 0.8% to 1.6%. Step 2: To find the exact optimum, more concentrations are needed close to 0.8%, with smaller intervals. Step 3: So extra readings between 0.4% and 1.6% around 0.8% are required.

Question 18 · Answer A

Step 1: Filtering separates the juice from the pulp using a funnel lined with filter paper. Step 2: Collecting the filtrate in a measuring cylinder lets the volume be read off a scale. Step 3: So a funnel with filter paper over a labelled measuring cylinder both filters and measures the juice.

Question 19 · 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 indicator colour is the dependent variable; the indicator stays red when photosynthesis equals respiration, so record the light intensity at which this happens. Step 3: Keep temperature, plant type and indicator volume constant and repeat the readings; only the first plan does all of this.