AQA GCSE Biology 2027 Predicted Practice Paper — Paper 1 Higher

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

Section A

Answer all questions. Use correct biological terms where possible.

• 1

  Question A1 (10 marks)

  A student investigated osmosis in plant tissue. They cut five identical cylinders from a raw beetroot, measured the mass of each, and placed one cylinder in each of five sucrose solutions of increasing concentration (0.0, 0.2, 0.4, 0.6 and 0.8 mol/dm^3). After 30 minutes each cylinder was removed, gently blotted and re-massed. The percentage change in mass was calculated for each cylinder. (a) Define the term osmosis. [2 marks] (b) One cylinder had a starting mass of 4.50 g and a final mass of 4.86 g. Calculate the percentage change in mass. [2 marks] (c) The cylinder in the 0.6 mol/dm^3 solution showed almost no change in mass. Explain what this result tells the student about the beetroot cells and the solution. [3 marks] (d) Identify two variables the student should control to make the investigation valid, and explain why each matters. [3 marks]

  (Total for Question A1 is 10 marks)
• 2

  Question A2 (10 marks)

  An enzyme called amylase breaks down starch into sugars. A technician mixed amylase with starch solution at 30 degrees C and, every 10 seconds, removed a drop and added it to iodine solution. When the iodine solution stopped turning blue-black, all the starch had been broken down. The starch was fully broken down after 40 seconds. (a) Explain why the iodine solution stops turning blue-black. [2 marks] (b) Calculate the rate of this reaction in units of 1/s (per second). Give your answer to 2 significant figures. [2 marks] (c) The technician repeated the experiment at 60 degrees C and found the starch was never fully broken down. Explain why, using ideas about enzyme structure. [4 marks] (d) Suggest one improvement to make the timing of the end point more accurate. [2 marks]

  (Total for Question A2 is 10 marks)
• 3

  Question A3 (8 marks)

  The cell cycle allows body cells to divide to produce two genetically identical daughter cells. (a) Name the type of cell division that produces two genetically identical daughter cells. [1 mark] (b) Describe what happens during the first stage of the cell cycle, before the cell divides. [3 marks] (c) In a sample of onion root tip cells, 120 cells were observed. 18 of them were undergoing mitosis. The complete cell cycle lasts 20 hours. Calculate the length of time, in hours, that a cell spends undergoing mitosis. Give your answer to 1 decimal place. [2 marks] (d) Give two reasons why cell division by this process is important in a multicellular organism. [2 marks]

  (Total for Question A3 is 8 marks)
• 4

  Question A4 (8 marks)

  Vaccines help protect people against communicable diseases caused by pathogens. (a) Describe how a vaccine leads to immunity against a specific pathogen. In your answer refer to antigens, antibodies and memory cells. [5 marks] (b) A new virus spreads through a population. Explain how a high level of vaccination in the population can protect people who are not themselves vaccinated. [3 marks]

  (Total for Question A4 is 8 marks)
• 5

  Question A5 (10 marks)

  Coronary heart disease (CHD) is a non-communicable disease. A study followed 4000 adults for 12 years and recorded whether they developed CHD. The results are shown below. Group 1 (non-smokers, normal body mass): 40 out of 1500 developed CHD. Group 2 (smokers, normal body mass): 96 out of 1200 developed CHD. Group 3 (smokers, obese): 143 out of 1300 developed CHD. (a) Calculate the percentage of Group 2 that developed CHD. Give your answer to 1 decimal place. [2 marks] (b) Using the data, evaluate whether smoking or obesity has the greater effect on the risk of developing CHD. [4 marks] (c) Explain how a build-up of fatty material in the coronary arteries can lead to a heart attack. [4 marks]

  (Total for Question A5 is 10 marks)

Section B

Answer all questions. Extended answers should be clear and logically ordered.

• 1

  Question B1 (10 marks)

  A student investigated the rate of photosynthesis of pondweed by counting the number of oxygen bubbles released per minute at different distances from a lamp. The lamp was the only light source. Distance 10 cm: 48 bubbles/min. Distance 20 cm: 12 bubbles/min. Distance 30 cm: 5 bubbles/min. (a) Write the balanced word equation for photosynthesis. [2 marks] (b) Light intensity is proportional to 1 / (distance^2). Use this relationship to explain why the rate at 20 cm is about one quarter of the rate at 10 cm. [3 marks] (c) At very high light intensities, increasing the light further did not increase the rate of photosynthesis. Name two factors that could be limiting the rate at this point, and for one of them explain how a grower could increase it in a greenhouse. [3 marks] (d) Counting bubbles is not a very reliable measure of the rate. Suggest a more valid measurement the student could make instead. [2 marks]

  (Total for Question B1 is 10 marks)
• 2

  Question B2 (12 marks)

  The human digestive system breaks down large insoluble food molecules into small soluble molecules. (a) Complete the following by naming the enzyme, the substrate it breaks down and the products, for each of the three main food groups: - carbohydrase (e.g. amylase) - protease - lipase For each, name one place in the digestive system where the enzyme is produced. [6 marks] (b) Bile is released into the small intestine. Explain two ways bile helps the digestion of lipids. [3 marks] (c) Describe how you would test a food sample for the presence of protein, including the expected positive result. [3 marks]

  (Total for Question B2 is 12 marks)
• 3

  Question B3 (10 marks)

  Stem cells are undifferentiated cells that can divide to form more cells of the same type or become specialised. (a) State what is meant by a differentiated cell. [2 marks] (b) Compare embryonic stem cells and adult stem cells in terms of the range of cell types each can produce. [2 marks] (c) Doctors can use stem cells to treat some medical conditions. Describe how stem cells could be used to treat a person with type 1 diabetes, and explain one advantage of using stem cells from the patient's own body. [3 marks] (d) Discuss one ethical objection and one practical risk associated with using embryonic stem cells in medicine. [3 marks]

  (Total for Question B3 is 10 marks)
• 4

  Question B4 (12 marks)

  Communicable diseases are caused by pathogens, which can be bacteria, viruses, fungi or protists. (a) Explain the difference between how bacteria and how viruses typically make us feel ill. [4 marks] (b) Describe three general ways in which the spread of a communicable disease can be reduced. For each, give a brief explanation of how it works. [3 marks] (c) Malaria is caused by a protist and is spread by mosquitoes. The mosquito is described as a vector. Explain what the term vector means, and describe two methods that could be used to reduce the spread of malaria. [3 marks] (d) The human body has non-specific defences that stop pathogens entering. Describe two of these defences. [2 marks]

  (Total for Question B4 is 12 marks)
• 5

  Question B5 (10 marks)

  Microscopes are used to study cells that are too small to see with the naked eye. (a) Give two differences between a light microscope and an electron microscope. [2 marks] (b) An image of a cell measured 60 mm across. The real width of the cell was 0.03 mm. Calculate the magnification of the image. Show your working. [2 marks] (c) A specialised animal cell contains many mitochondria. Explain what this suggests about the function of the cell. [3 marks] (d) Describe three structures found in a plant cell that are NOT found in an animal cell, and state the function of each. [3 marks]

  (Total for Question B5 is 10 marks)