Pearson Edexcel Level 3 GCE

e examination details below before entering your candidate information Candidate surname Other names Centre Number Candidate Number Pearson Edexcel Level 3 GCE Monday 12 May 2025 reference 8BN0/01 Biology A (Salters Nuffield) Total Marks Instructions • Use black ink or ball‑point pen. centre number and candidate number. • Show all your working out in calculations and include units where appropriate. – there may be more space than you need. Information • The total mark for this paper is 80. – use this as a guide as to how much time to spend on each question. In questions marked with an asterisk (*), marks will be awarded for your ability to structure your answer logically, showing how the points that you make are related or follow on from each other where appropriate. Advice • Read each question carefully before you start to answer it. • Check your answers if you have time at the end. Turn over P78687A ©2025 Pearson Education Ltd. Y:1/1/1/1/ Answer ALL questions. Write your answers in the spaces provided. Some questions must be answered with a cross in a box . If you change your mind about an answer, put a line through the box and then mark your new answer with a cross . 1 DNA and RNA are nucleic acids. (a) (i) Which base is present in RNA but absent from DNA? A adenine B guanine C thymine D uracil (ii) Which row shows the correct structure of these two molecules? A B C D (b) DNA acts as a template for the synthesis of messenger RNA. (i) Which bond joins together mononucleotides in a strand of DNA and RNA? A disulfide B glycosidic C peptide D phosphodiester (1) (1) (1) (ii) Give three differences between the process of DNA replication and the process of DNA transcription. 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(Total for Question 1 = 6 marks) 2 The diagram shows some components of a cell membrane. ion P Q R ATP ADP S T glucose molecule (a) The components labelled P and T are proteins. (i) State one role of ATP in the movement of molecules through the component labelled T. (1) ............................................................................................................................... ............................................................................................................................... ...................... ............................................................................................................................... ............................................................................................................................... ...................... ............................................................................................................................... ............................................................................................................................... ...................... (ii) Describe how ions enter the cell through the component labelled P. 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(b) The components labelled Q, R and S are phospholipids. (i) Water molecules can pass between phospholipids to enter or leave a cell. Name this process. (1) ............................................................................................................................... ............................................................................................................................... ...................... (ii) Explain why the phospholipids labelled Q and R have different shapes. 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(iii) Predict the effect of increasing the proportion of the phospholipid labelled S on one of the properties of this cell membrane. (1) ............................................................................................................................... ............................................................................................................................... ...................... ............................................................................................................................... ............................................................................................................................... ...................... ............................................................................................................................... ............................................................................................................................... ...................... (Total for Question 2 = 7 marks) 3 The phenotype of an organism is affected by its genotype. Chickens have different patterns and colours in their feathers as a result of their genotypes. The image shows the genotypes and phenotypes of two chickens used in a breeding programme and one of their offspring. A gene has the alleles B and W. black BB white WW white with black flecks BW (a) (i) State what is meant by the following terms. Genotype (2) ............................................................................................................................... ............................................................................................................................... ...................... ............................................................................................................................... ............................................................................................................................... ...................... Phenotype ............................................................................................................................... ............................................................................................................................... ...................... ............................................................................................................................... ............................................................................................................................... ...................... (ii) Explain the type of inheritance shown in this example. 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(b) Two chickens, both white with black flecks, were used in a further breeding programme. (i) Draw a genetic diagram to find the expected ratio of the phenotypes of the offspring. (3) Ratio of named phenotypes: ............................................................................................................................... ............................................................................................................................... ...................... (ii) A statistical test can be used to compare observed and expected frequencies of the different phenotypes. Which statistical test is used to compare observed and expected frequencies of the different phenotypes? A chi‑squared test B correlation coefficient C standard deviation D Student’s t‑test (1) (Total for Question 3 = 8 marks) 4 Vitamin C can be found in many fruits and vegetables, including broccoli. The table shows the vitamin C content of two types of broccoli. Type of broccoli Mean vitamin C content / µg per cm3 extract Green broccoli 30 Purple‑sprouting broccoli 25 (a) It is recommended that a pregnant woman consumes 85 mg of vitamin C a day. Calculate the volume of purple‑sprouting broccoli extract that would provide 85 mg of vitamin C. Give your answer in dm3. (3) . dm3 (b) The photograph shows green broccoli being cooked in a steamer. (Source: © Art Directors & TRIP / Alamy Stock Photo) Broccoli can also be cooked by boiling in water. A student investigated the following hypothesis: ‘The broccoli will lose less vitamin C if it is steamed than if it is boiled’. Devise an investigation the student could use to test this hypothesis and collect valid data. 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Some studies have discovered a negative correlation between vitamin C intake and the risk of coronary heart disease. State what is meant by a negative correlation between vitamin C intake and the risk of coronary heart disease. 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(Total for Question 4 = 9 marks) 5 The graph shows the pressure changes in the left ventricle of a human heart. 16 14 12 10 Pressure / kPa 8 6 4 2 0 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 Time / s (a) (i) Draw a line on the graph to show the pressure changes in the right ventricle from 0.16 to 0.44 seconds. (ii) Calculate the heart rate shown in the graph. (1) (1) . beats min–1 (iii) Which correctly describes the blood as it moves out of the left ventricle? (1) A deoxygenated and pumped into the aorta B deoxygenated and pumped into the pulmonary artery C oxygenated and pumped into the aorta D oxygenated and pumped into the pulmonary artery (iv) Explain what is causing the change in pressure in the left ventricle during the following time periods: 0.0 to 0.08 seconds (4) ............................................................................................................................... ............................................................................................................................... ...................... ............................................................................................................................... ............................................................................................................................... ...................... ............................................................................................................................... ............................................................................................................................... ...................... ............................................................................................................................... ............................................................................................................................... ...................... ............................................................................................................................... ............................................................................................................................... ...................... ............................................................................................................................... ............................................................................................................................... ...................... ............................................................................................................................... ............................................................................................................................... ...................... 0.16 to 0.3 seconds ............................................................................................................................... ............................................................................................................................... ...................... ............................................................................................................................... ............................................................................................................................... ...................... ............................................................................................................................... ............................................................................................................................... ...................... ............................................................................................................................... ............................................................................................................................... ...................... ............................................................................................................................... ............................................................................................................................... ...................... ............................................................................................................................... ............................................................................................................................... ...................... ............................................................................................................................... ............................................................................................................................... ...................... (b) The lumen of a coronary artery can be widened by a technique called angioplasty. A stent can be used to maintain the lumen width of the coronary artery after angioplasty has occurred. The image shows a stent in a coronary artery. stent (Source: © Stocktrek Images, Inc. / Alamy Stock Photo) (i) Explain why a patient might need this treatment.