2023 Cambridge IGCSE Biology (0610) Practice Paper with Answers

Under which set of environmental conditions will a leafy shoot experience the highest rate of transpiration?

Which row correctly identifies the state of the heart valves when the ventricles are contracting?

Which row correctly identifies a substance that is filtered from the blood into the Bowman's capsule and its status of reabsorption in a healthy kidney?

A student performs food tests on an unknown liquid sample. The results are: Biuret test turns purple; Ethanol emulsion test forms a cloudy white emulsion; Iodine test remains yellow-brown. Which biological molecules are present in this sample?

Cylinders of potato tissue of equal initial length were placed in sucrose solutions of different concentrations. After two hours, cylinder P decreased in length, while cylinder Q increased in length. Which statement about water potential is correct?

In a species of plant, the allele for red flowers (R) is dominant to the allele for white flowers (r). A heterozygous red-flowered plant is crossed with a white-flowered plant. What is the expected ratio of phenotypes in the offspring?

Which sequence of events is correct during the production of human insulin by genetically modified bacteria?

Which statement best describes the effect of increasing the temperature from 20 to 80 degrees Celsius on an enzyme-catalyzed reaction?

A student set up a potometer to measure the rate of water uptake of a leafy shoot. She wants to investigate the effect of humidity. How can she increase the humidity around the shoot, and what will be the effect on the rate of movement of the bubble in the capillary tube?

During ventricular contraction (systole) in the human heart, what is the state of the valves?

Which comparison of the blood entering a healthy kidney via the renal artery and leaving it via the renal vein is correct?

A solution of an unknown food substance was tested with different reagents. The results were as follows: Iodine test was blue-black; Benedict's test (heated) remained blue; Biuret test was purple; Ethanol emulsion test remained clear and colourless. Which biological molecules are present in this food substance?

Four cubes of agar gel containing a pH indicator are placed into a beaker of dilute hydrochloric acid. The acid diffuses into the cubes, turning them from pink to colourless. The side lengths of the cubes are: Cube 1: 0.5 cm; Cube 2: 1.0 cm; Cube 3: 2.0 cm; Cube 4: 3.0 cm. Which cube will take the longest time to become completely colourless?

Equal-sized cylinders of potato tissue were placed in sucrose solutions of different concentrations: P, Q, R, and S. After two hours, the change in length of each cylinder was recorded: Cylinder in P increased in length; Cylinder in Q decreased in length; Cylinder in R showed no change in length; Cylinder in S decreased significantly in length. Which sequence shows the sucrose solutions ordered from lowest concentration of sucrose to highest concentration of sucrose?

In a certain plant species, flower colour is determined by two codominant alleles: \(C^R\) (red) and \(C^W\) (white). Heterozygous individuals (\(C^R C^W\)) produce pink flowers. If a pink-flowered plant is crossed with a white-flowered plant, what is the expected ratio of phenotypes in the offspring?

Which of the following is a key ecological reason for conserving endangered animal species in their natural habitats?

Under which combination of environmental conditions will the rate of transpiration from a leafy shoot be lowest?

Which row correctly identifies the chamber of the heart that pumps deoxygenated blood to the lungs and the main blood vessel that carries oxygenated blood to the rest of the body?

In the human kidney, which structures are responsible for ultrafiltration and the selective reabsorption of glucose?

A student tests a liquid food sample and records the following results: Iodine test remains orange-brown; Biuret test turns purple; Ethanol emulsion test remains clear; Benedict's test turns red after heating. Which nutrients are present in the food sample?

Which changes would cause the greatest increase in the rate of diffusion of oxygen across a cell membrane?

Plant cells with a cytoplasm water potential equivalent to a 0.4 mol/dm3 sucrose solution are placed in different test tubes. In which concentration of sucrose solution will the cells become turgid?

In a plant species, the allele for red flowers (R) is dominant over the allele for white flowers (r). A heterozygous plant is crossed with a white-flowered plant. What is the expected ratio of phenotypes in the offspring?

Which statement represents an ecological reason for conserving a tropical rainforest ecosystem?

A student measures the rate of water uptake of a leafy shoot using a potometer under different conditions. In set-up X, they place a fan blowing air past the shoot. In set-up Y, they cover the plant with a clear plastic bag. In set-up Z, they increase the room temperature from \(20^\circ\text{C}\) to \(30^\circ\text{C}\). Which combination of changes to the environmental conditions will decrease the rate of transpiration compared to the control (still air, \(20^\circ\text{C}\), uncovered)?

A student uses a potometer to measure the rate of water uptake of a leafy shoot. Which combination of environmental factors will result in the shortest time for the bubble to move a distance of 10 cm?

The human heart consists of four muscular chambers. Which chamber contracts to pump oxygenated blood at the highest pressure to the rest of the body, and what structural feature allows this?

During ultrafiltration in the human kidney, which substances from the blood pass into the Bowman's capsule, and which substance is fully reabsorbed back into the blood at the proximal convoluted tubule under normal conditions?

A student tests a liquid food sample using three reagents. The Benedict's test (after heating) gives a brick-red precipitate, the Biuret test turns violet, and the iodine test remains orange-brown. Which biological molecules are present in this food sample?

Under which set of conditions will the rate of diffusion of gas molecules across a membrane be the highest?

An epidermal cell from a red onion is placed in a highly concentrated sucrose solution. What is the net direction of water movement and the resulting state of the cell?

In a type of plant, the allele for red flowers (R) is dominant to the allele for white flowers (r). Two heterozygous plants are crossed. What is the probability that an offspring will have white flowers?

Which conservation strategy provides the most sustainable balance between protecting endangered wildlife and supporting the local human population?

(a) Define the term transpiration. [2] (b) Describe how a student would use a bubble potometer to estimate the rate of water uptake in a leafy shoot. Include one precaution that must be taken when setting up the apparatus. [4] (c) Explain, in terms of water potential gradient and kinetic energy of water molecules, how increasing the wind speed affects the rate of transpiration. [3] (d) State two anatomical adaptations of xerophytic leaves that reduce water loss. [2]

(a) Name the blood vessels that supply the muscle tissue of the heart with oxygen and nutrients, and explain the consequences of these vessels becoming blocked. [4] (b) The muscular wall of the left ventricle is significantly thicker than that of the right ventricle. Explain the physiological importance of this structural difference. [3] (c) Describe the function of the septum in the mammalian heart. [2] (d) State two lifestyle factors, other than diet, that increase the risk of developing coronary heart disease (CHD). [2]

(a) Define excretion and name two toxic waste substances, excluding carbon dioxide, excreted by the human kidney. [3] (b) Describe the process of ultrafiltration in the renal corpuscle (glomerulus and Bowman's capsule). [4] (c) State the exact region of the nephron where glucose is selectively reabsorbed and the transport process used. [2] (d) Dehydration leads to the production of concentrated urine. Explain how the body adjusts urine concentration in response to low water potential of the blood. [2]

(a) Describe how you would test a liquid food sample to demonstrate the presence of: (i) reducing sugars, and (ii) proteins. Include the names of the reagents used and the positive color results. [4] (b) State the four main chemical elements present in all proteins and identify the specific element present in proteins but absent in lipids and carbohydrates. [3] (c) Explain how the unique sequence of amino acids determines the function of an enzyme. [2] (d) Describe the structural shape of a DNA molecule and name the complementary base pairs. [2]

(a) Define the term osmosis. [3] (b) A group of students placed potato cylinders into a concentrated sucrose solution. After 2 hours, they observed a decrease in the mass of the cylinders. Explain this observation in terms of water potential. [4] (c) Describe the appearance of a plant cell that has lost a large volume of water by osmosis and state the term used to describe this condition. [2] (d) Explain why a human red blood cell lyses (bursts) when placed in distilled water, whereas a plant cell does not. [2]

(a) Define the term endangered species and list two human activities that can cause a species to become endangered. [3] (b) Explain how the implementation of (i) fishing quotas and (ii) large-mesh size nets can help to conserve wild fish populations. [4] (c) Explain why it is important to conserve ecosystems and maintain biodiversity. [4]

(a) Define the term enzyme and explain the lock and key hypothesis of enzyme action. [4] (b) Describe and explain the effect of: (i) a low temperature of 5 degrees C and (ii) an extremely high temperature of 70 degrees C on the rate of an enzyme-controlled reaction. [4] (c) State three variables that must be controlled when investigating the effect of pH on the activity of salivary amylase. [3]

An investigation was carried out to study the effect of wind speed on the rate of transpiration from a leafy shoot. A student set up a balance with a conical flask containing water and a leafy shoot. A layer of oil was placed on top of the water to prevent evaporation. A fan was set up at different distances from the shoot to vary the wind speed: 10 cm, 30 cm, and 50 cm. A control experiment was also set up with no fan. The mass of the flask was measured at the start and after exactly 2 hours. The results are as follows: (i) No fan: Start mass = 152.4 g, End mass = 150.8 g. (ii) 50 cm distance: Start mass = 151.8 g, End mass = 148.6 g. (iii) 30 cm distance: Start mass = 153.1 g, End mass = 148.3 g. (iv) 10 cm distance: Start mass = 150.5 g, End mass = 143.7 g. Tasks: 1. Calculate the mass loss (g) for each condition, and then calculate the rate of water loss in grams per hour (g/h). [4 marks] 2. Identify the independent variable and the dependent variable in this investigation. [2 marks] 3. Explain why a layer of oil was added to the surface of the water in each flask. [2 marks] 4. Describe how you would plot a line graph of these results, stating what should be on each axis and the trend you would expect to see for the distances 10 cm, 30 cm, and 50 cm. [4 marks] 5. Identify two variables (other than wind speed) that must be kept constant (controlled variables) during this investigation, and describe how they could be controlled. [4 marks] 6. Describe a chemical test the student could use to confirm that the liquid lost by the plant is water, including the expected positive result. [4 marks]

Catalase is an enzyme found in plant tissues, such as potato, which breaks down hydrogen peroxide to form water and oxygen gas. Part 1: A student drew a diagram of a potato cell observed under a light microscope. The length of the cell in the drawing is 62 mm. The actual length of the cell is 0.08 mm. 1. Calculate the magnification of the student's drawing. Show your working and state the answer to the nearest whole number. [3 marks] 2. State two rules of biological drawing that the student should follow to ensure their diagram is scientific. [2 marks] Part 2: Plan an investigation to determine the effect of temperature on the rate of oxygen production by potato catalase. Include details of the apparatus, how you will vary the temperature, which variables you will control, how you will measure the dependent variable, and how you will ensure the results are reliable. [6 marks] Part 3: The student carried out a preliminary experiment to compare the catalase activity in raw potato and cooked (boiled) potato. They measured the volume of oxygen gas produced in 3 minutes. Raw potato trials: 12.4 cm3, 13.0 cm3, 12.1 cm3. Cooked potato trials: 0.0 cm3, 0.0 cm3, 0.0 cm3. 3. Calculate the mean volume of gas produced by the raw potato. Show your working and round your answer to one decimal place. [2 marks] 4. Explain the difference in the volume of oxygen gas produced between raw potato and cooked potato. [3 marks] 5. Describe a biochemical test the student could use to confirm that the potato tissue contains starch, including the positive result. [2 marks] 6. State one safety hazard associated with using hydrogen peroxide and suggest an appropriate precaution. [2 marks]