OCR GCSE Biology 2027 Predicted Practice Paper — Paper 4 Higher

Answer ALL questions. Write your answers in the spaces provided. You must write down all the stages in your working.

Section A

Multiple choice questions. Answer ALL the questions.

• 1

  Question SECTION-A1 (1 mark)

  Which structure in a plant cell is the site of photosynthesis?

  A. RibosomeB. ChloroplastC. MitochondrionD. Vacuole

  (Total for Question SECTION-A1 is 1 mark)
• 2

  Question SECTION-A2 (1 mark)

  A student estimates the number of daisies in a field using a quadrat and mean count. This method gives an estimate of population size because it:

  A. Counts every daisy in the whole fieldB. Samples a small area and scales up to the total areaC. Measures the biomass of each daisyD. Records only the largest daisies present

  (Total for Question SECTION-A2 is 1 mark)
• 3

  Question SECTION-A3 (1 mark)

  Which row correctly describes deoxygenated blood entering the human heart?

  A. Enters the left atrium from the pulmonary veinB. Enters the right atrium from the vena cavaC. Enters the left ventricle from the aortaD. Enters the right ventricle from the pulmonary artery

  (Total for Question SECTION-A3 is 1 mark)
• 4

  Question SECTION-A4 (1 mark)

  An enzyme-controlled reaction is measured at several temperatures. The rate is highest at 40 degrees C and much lower at 60 degrees C. The best explanation for the low rate at 60 degrees C is that the enzyme has:

  A. Been used up by the reactionB. Been denatured, changing the shape of its active siteC. Reacted with the productD. Increased its optimum temperature

  (Total for Question SECTION-A4 is 1 mark)
• 5

  Question SECTION-A5 (1 mark)

  Which process moves water across a partially permeable membrane from a dilute to a more concentrated solution?

  A. Active transportB. Diffusion of soluteC. OsmosisD. Translocation

  (Total for Question SECTION-A5 is 1 mark)
• 6

  Question SECTION-A6 (1 mark)

  A gene has two alleles: B (brown, dominant) and b (blue, recessive). Two heterozygous parents are crossed. What proportion of offspring are expected to show the blue phenotype?

  A. 1 in 4B. 1 in 2C. 3 in 4D. 0 in 4

  (Total for Question SECTION-A6 is 1 mark)
• 7

  Question SECTION-A7 (1 mark)

  Which hormone reduces blood glucose concentration by stimulating liver and muscle cells to take up glucose?

  A. GlucagonB. InsulinC. AdrenalineD. Testosterone

  (Total for Question SECTION-A7 is 1 mark)
• 8

  Question SECTION-A8 (1 mark)

  In a food chain, only about 10 percent of biomass is transferred between trophic levels. The main reason biomass is lost is that organisms:

  A. Grow larger at each levelB. Use energy in respiration and lose material in wasteC. Absorb minerals from the soilD. Reflect light from their surfaces

  (Total for Question SECTION-A8 is 1 mark)
• 9

  Question SECTION-A9 (1 mark)

  Which statement about aerobic and anaerobic respiration in humans is correct?

  A. Aerobic respiration produces lactic acidB. Anaerobic respiration releases more energy per glucose moleculeC. Aerobic respiration requires oxygen and produces carbon dioxide and waterD. Anaerobic respiration produces ethanol in human muscle cells

  (Total for Question SECTION-A9 is 1 mark)
• 10

  Question SECTION-A10 (1 mark)

  A gardener takes cuttings from a plant and grows them into new plants. The new plants are genetically identical to the parent because they are produced by:

  A. Sexual reproduction involving gametesB. Asexual reproduction by mitosisC. Meiosis in the flowersD. Random fertilisation

  (Total for Question SECTION-A10 is 1 mark)
• 11

  Question SECTION-A11 (1 mark)

  Which of the following is a correct description of a reflex arc pathway?

  A. Receptor -> motor neurone -> relay neurone -> sensory neurone -> effectorB. Receptor -> sensory neurone -> relay neurone -> motor neurone -> effectorC. Effector -> motor neurone -> relay neurone -> sensory neurone -> receptorD. Receptor -> relay neurone -> sensory neurone -> motor neurone -> effector

  (Total for Question SECTION-A11 is 1 mark)
• 12

  Question SECTION-A12 (1 mark)

  Antibiotic-resistant bacteria have become more common. This is an example of:

  A. Inheritance of acquired characteristicsB. Natural selection acting on random mutationsC. Bacteria deciding to change to surviveD. Selective breeding by scientists

  (Total for Question SECTION-A12 is 1 mark)
• 13

  Question SECTION-A13 (1 mark)

  Which adaptation increases the rate of gas exchange in the human lungs?

  A. A thick, waterproof surfaceB. A small surface area to volume ratioC. A large surface area of moist, thin alveoli with a good blood supplyD. A dry lining to prevent gases dissolving

  (Total for Question SECTION-A13 is 1 mark)
• 14

  Question SECTION-A14 (1 mark)

  A restriction enzyme is used in genetic engineering to:

  A. Join two pieces of DNA togetherB. Cut DNA at specific base sequencesC. Copy DNA to make many identical strandsD. Translate mRNA into protein

  (Total for Question SECTION-A14 is 1 mark)
• 15

  Question SECTION-A15 (1 mark)

  Which change would most likely reduce the biodiversity of a woodland ecosystem?

  A. Planting a wide variety of native tree speciesB. Introducing hedgerows between fieldsC. Deforestation to create a single-crop plantationD. Reducing the use of pesticides

  (Total for Question SECTION-A15 is 1 mark)

Section B

Structured and extended response questions. Answer ALL the questions.

• 1

  Question SECTION-B1 (5 marks)

  A student investigates the effect of light intensity on the rate of photosynthesis in pondweed. A lamp is placed at different distances from the pondweed and the number of oxygen bubbles released per minute is counted. (a) State the independent variable and the dependent variable in this investigation. (b) Give two variables the student should control to make it a fair test. (c) Explain, in terms of a limiting factor, why the bubble rate stops increasing at very high light intensities even though the light gets brighter.

  (Total for Question SECTION-B1 is 5 marks)
• 2

  Question SECTION-B2 (6 marks)

  Homeostasis keeps the internal environment of the body within narrow limits. (a) Define the term homeostasis. (b) Body temperature is controlled by negative feedback. Describe how the body responds when core temperature rises above normal, including the roles of the skin. (c) Explain why maintaining a stable core temperature is important for enzyme-controlled reactions in the body.

  (Total for Question SECTION-B2 is 6 marks)
• 3

  Question SECTION-B3 (6 marks)

  Cystic fibrosis is a genetic disorder caused by a recessive allele (f). The dominant allele (F) codes for the unaffected condition. A couple who are both carriers (heterozygous) plan to have children. (a) State what is meant by the term carrier. (b) Draw a genetic (Punnett) cross to show the possible genotypes of their children. (c) State the probability that a child will have cystic fibrosis, and the probability that a child will be a carrier. (d) Explain why two unaffected parents can have a child with cystic fibrosis.

  (Total for Question SECTION-B3 is 6 marks)
• 4

  Question SECTION-B4 (5 marks)

  The rate of transpiration from a plant was measured using a potometer over one hour under four sets of conditions. Results (cm^3 of water uptake per hour): still air = 2.0; windy = 4.5; high humidity = 0.9; bright light = 3.6. (a) Calculate the percentage increase in water uptake when moving from still air to windy conditions. (b) Explain why increasing wind speed increases the rate of transpiration. (c) Explain why high humidity decreases the rate of transpiration.

  (Total for Question SECTION-B4 is 5 marks)
• 5

  Question SECTION-B5 (6 marks)

  A new medicine to lower blood pressure must be tested before it can be used by patients. Describe the main stages of testing a new drug, from initial laboratory work through to use in patients. Your answer should refer to preclinical testing, clinical trials, and the use of placebos and double-blind trials.

  (Total for Question SECTION-B5 is 6 marks)
• 6

  Question SECTION-B6 (5 marks)

  The human digestive system produces enzymes to break down large food molecules. (a) Name the enzyme that digests starch and state the products of this reaction. (b) Bile is released into the small intestine. Describe two functions of bile and explain how each aids digestion. (c) Describe a simple test the student could carry out to show that a sample of food contains reducing sugars, and give the positive result.

  (Total for Question SECTION-B6 is 5 marks)
• 7

  Question SECTION-B7 (8 marks)

  Read the information, then answer the question. A remote island has a population of finches that feed on seeds. In a dry year, only large, hard seeds are available. Finches with larger, stronger beaks can crack these seeds; finches with small beaks cannot and many die before breeding. Over several generations the average beak size in the population increases. (a) Explain how this change in average beak size is an example of natural selection. Use the ideas of variation, competition, survival and inheritance in your answer. (b) State what would be needed for these finches to be classed as a new species. (c) Suggest one reason why fossil evidence for beak-size evolution in small birds may be incomplete.

  (Total for Question SECTION-B7 is 8 marks)
• 8

  Question SECTION-B8 (6 marks)

  The carbon cycle recycles carbon between the atmosphere, living organisms and the environment. (a) Name the process that removes carbon dioxide from the atmosphere and the process carried out by all living organisms that returns it. (b) Describe the role of microorganisms (decomposers) in the carbon cycle. (c) Explain how the burning of fossil fuels and large-scale deforestation can together increase the concentration of carbon dioxide in the atmosphere.

  (Total for Question SECTION-B8 is 6 marks)
• 9

  Question SECTION-B9 (5 marks)

  Type 2 diabetes is a non-communicable disease linked to lifestyle. (a) Describe how the body of a person without diabetes controls a rise in blood glucose after a meal. (b) Explain why a person with Type 2 diabetes has difficulty controlling their blood glucose. (c) Suggest two lifestyle changes that can help control Type 2 diabetes and, for one of them, explain how it helps.

  (Total for Question SECTION-B9 is 5 marks)
• 10

  Question SECTION-B10 (6 marks)

  A scientist studies the distribution of a species of moss growing on a woodland floor, from the edge of a clearing into dense shade. (a) Describe how the scientist could use a transect and quadrats to investigate how the abundance of moss changes with distance into the shade. (b) The scientist finds moss is more abundant in the shade. Suggest one abiotic factor that could explain this and justify your suggestion. (c) Explain why taking measurements at several points along the transect, and repeating the whole transect in different parts of the wood, improves the investigation.

  (Total for Question SECTION-B10 is 6 marks)
• 11

  Question SECTION-B11 (4 marks)

  Vaccination protects people against communicable diseases. (a) Describe how a vaccine produces immunity against a specific pathogen, referring to antigens, white blood cells and antibodies. (b) Explain what is meant by herd immunity and why it protects people who have not been vaccinated.

  (Total for Question SECTION-B11 is 4 marks)
• 12

  Question SECTION-B12 (7 marks)

  The graph of a reaction shows that as substrate concentration increases, the rate of an enzyme-controlled reaction rises and then levels off (plateaus). (a) Explain, in terms of the enzyme and substrate, why the rate rises as substrate concentration increases at low concentrations. (b) Explain why the rate levels off at high substrate concentrations. (c) Describe how you would change and control conditions to investigate the effect of pH on the rate of this enzyme reaction, and identify one hazard you would manage.

  (Total for Question SECTION-B12 is 7 marks)
• 13

  Question SECTION-B13 (6 marks)

  Selective breeding and genetic engineering are two ways of producing organisms with desired characteristics. (a) Describe the process of selective breeding to produce cattle that give more milk. (b) Give one advantage of genetic engineering over selective breeding. (c) Discuss one benefit and one concern associated with genetically modifying crops.

  (Total for Question SECTION-B13 is 6 marks)