WJEC/Eduqas GCSE Biology 2027 Predicted Practice Paper — Component 1

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

Section A

Short-answer and structured questions. Answer ALL questions.

• 1

  Question SECTION-A1 (5 marks)

  A student examined a prepared slide of a leaf palisade mesophyll cell and a slide of a bacterial cell from a pond. (a) State two structures that are present in the palisade cell but ABSENT from the bacterial cell. [2] (b) The bacterial cell contains a small circular loop of DNA that is separate from its main genetic material. Name this structure and state one way it is useful to the bacterium. [2] (c) Explain why the palisade cell contains many chloroplasts whereas a root hair cell from the same plant contains none. [1]

  (Total for Question SECTION-A1 is 5 marks)
• 2

  Question SECTION-A2 (4 marks)

  The diagram of a section through the human breathing system shows the trachea, bronchi, bronchioles and alveoli. State two features of an alveolus that make it well adapted for efficient gas exchange, and for EACH feature state how it helps. [4]

  (Total for Question SECTION-A2 is 4 marks)
• 3

  Question SECTION-A3 (5 marks)

  An enzyme called amylase breaks down starch into maltose. A student measured the time taken for amylase to fully digest a fixed mass of starch at different temperatures. Results: 10 degrees C = 300 s; 20 degrees C = 160 s; 30 degrees C = 90 s; 40 degrees C = 50 s; 50 degrees C = 180 s; 60 degrees C = no digestion. (a) Calculate the rate of reaction at 30 degrees C in arbitrary units, using rate = 1000 / time. Give your answer to the nearest whole number. [2] (b) Explain, in terms of the enzyme, why NO digestion occurred at 60 degrees C. [3]

  (Total for Question SECTION-A3 is 5 marks)
• 4

  Question SECTION-A4 (4 marks)

  Blood glucose concentration is controlled by negative feedback. After a meal high in carbohydrate, the blood glucose concentration of a healthy person rises. (a) Name the organ that detects the rise in blood glucose and releases a hormone in response. [1] (b) Name this hormone and state the effect it has on liver cells that lowers blood glucose. [2] (c) Explain what is meant by the term 'negative feedback' using this example. [1]

  (Total for Question SECTION-A4 is 4 marks)
• 5

  Question SECTION-A5 (5 marks)

  A gardener investigated the effect of light intensity on the rate of photosynthesis of pondweed by counting bubbles of gas released per minute at different distances from a lamp. As the lamp was moved closer, the bubble rate increased then levelled off at high light intensities. (a) Name the gas in the bubbles. [1] (b) Explain why the rate increased as the lamp was moved closer to the pondweed. [2] (c) At high light intensities the rate levelled off. Name two factors, other than light, that could be limiting the rate at this point. [2]

  (Total for Question SECTION-A5 is 5 marks)
• 6

  Question SECTION-A6 (4 marks)

  In pea plants, the allele for tall stems (T) is dominant to the allele for short stems (t). A heterozygous tall plant was crossed with a short plant. (a) State the genotype of the short parent plant. [1] (b) Draw a genetic (Punnett) cross to show the genotypes of the offspring, and state the expected ratio of tall to short offspring. [3]

  (Total for Question SECTION-A6 is 4 marks)
• 7

  Question SECTION-A7 (5 marks)

  A reflex action allows the body to respond quickly to a harmful stimulus, such as touching a sharp thorn. (a) Describe the pathway of a nerve impulse in a reflex arc, from the stimulus to the response, naming the types of neurone involved and the role of the synapse. [4] (b) State one advantage of a reflex action being automatic (involuntary). [1]

  (Total for Question SECTION-A7 is 5 marks)
• 8

  Question SECTION-A8 (5 marks)

  The carbon cycle recycles carbon between living organisms and the environment. (a) Name the process by which plants remove carbon dioxide from the atmosphere. [1] (b) Name two processes that RETURN carbon dioxide to the atmosphere. [2] (c) Explain how the carbon locked in a dead animal is eventually released back into the atmosphere as carbon dioxide. [2]

  (Total for Question SECTION-A8 is 5 marks)
• 9

  Question SECTION-A9 (5 marks)

  Two potato cylinders of equal mass were placed in different sucrose solutions for 30 minutes. Cylinder A was placed in distilled water and gained mass. Cylinder B was placed in a concentrated sucrose solution and lost mass. (a) Name the process responsible for the mass changes. [1] (b) Explain, in terms of water potential and the movement of water molecules, why cylinder A gained mass. [2] (c) Explain why cylinder B lost mass. [2]

  (Total for Question SECTION-A9 is 5 marks)
• 10

  Question SECTION-A10 (5 marks)

  Vaccination protects people against infectious disease. A vaccine contains a dead or weakened form of a pathogen, or its antigens. (a) Explain how a vaccine produces long-term immunity against a specific pathogen. [4] (b) Explain what is meant by 'herd immunity' and why it protects people who have not been vaccinated. [1]

  (Total for Question SECTION-A10 is 5 marks)
• 11

  Question SECTION-A11 (6 marks)

  A food chain in a rocky shore ecosystem is: microscopic algae -> limpets -> crabs -> gulls. (a) Name the trophic level occupied by the crabs. [1] (b) The energy available at each trophic level decreases along the chain. Give two reasons why energy is lost between trophic levels. [2] (c) A pyramid of biomass for this food chain has a much smaller bar for gulls than for limpets. Explain why, referring to energy transfer efficiency. [3]

  (Total for Question SECTION-A11 is 6 marks)
• 12

  Question SECTION-A12 (5 marks)

  Antibiotics are medicines used to treat bacterial infections. In recent years some strains of bacteria have become resistant to antibiotics. (a) Explain, using ideas about natural selection, how a population of bacteria can become resistant to an antibiotic. [4] (b) State one action doctors or patients can take to help slow down the development of antibiotic resistance. [1]

  (Total for Question SECTION-A12 is 5 marks)

Section B

Extended response questions. Answer ALL questions.

• 1

  Question SECTION-B1 (8 marks)

  The kidneys maintain the correct water balance of the blood by osmoregulation, controlled by the hormone ADH (antidiuretic hormone) using negative feedback. On a hot day a person sweats heavily and does not drink any water. Describe and explain how the hormonal control system responds to return the blood water content to normal, and describe how the response would differ if the person then drank a large volume of water. [8]

  (Total for Question SECTION-B1 is 8 marks)
• 2

  Question SECTION-B2 (8 marks)

  Cystic fibrosis is a genetic disorder caused by a recessive allele (f). A couple who do not have cystic fibrosis already have one child who has the disorder. (i) Explain what this tells you about the genotypes of the two parents. (ii) Draw a genetic diagram to determine the probability that their next child will have cystic fibrosis, and the probability that a child who does NOT have the disorder is a carrier. (iii) Discuss one ethical or practical issue raised by genetic screening of embryos for disorders such as cystic fibrosis. [8]

  (Total for Question SECTION-B2 is 8 marks)
• 3

  Question SECTION-B3 (6 marks)

  A team of ecologists investigated whether a species of woodland wildflower is more abundant in a clearing (high light) than under dense tree cover (low light). They used quadrats along a transect running from the clearing into the wood. (i) Describe a valid method they could use to compare the mean number of wildflowers per quadrat in the two areas, including how they would make the investigation fair and reliable. (ii) Explain how light intensity could account for any difference in abundance they find. [6]

  (Total for Question SECTION-B3 is 6 marks)