AQA GCSE Biology Paper 1 - Specimen paper with mark scheme 2022

1.1 Plants move mineral ions: • from a low concentration in the soil • to a high concentration in the root cells. What process do plants use to move these minerals ions into root cells? [1 mark] Tick one box. Active transport Diffusion Evaporation Osmosis - ANSWER-Active Transport 1.2 Describe how water moves from roots to the leaves - ANSWER-by transpiration stream / pull in xylem 1.3 Plants lose water through the stomata in the leaves. The epidermis can be peeled from a leaf. The stomata can be seen using a light microscope. Table 1 shows the data a student collected from five areas on one leaf. Describe how the student might have collected the data in Table 1. - ANSWER-any three in the correct order from: • mount epidermis on a slide • count stomata in one area • repeat in four more areas • repeat method on other surface of leaf • calculate mean 1.4 What is the median number of stomata on the upper surface of the leaf? - ANSWER-1 1.5 Calculate the value of X in Table 1. Give your answer to 2 significant figures. [2 marks] - ANSWER-(44 + 41 + 40 + 42 + 39) / 5 = 41.2 41 1.6 The plant used in this investigation has very few stomata on the upper surface of the leaf. Explain why this is an advantage to the plant. [2 marks] - ANSWER-less water lost so it does not wilt 2.1 All tools should be washed in disinfectant after using them on plants infected with TMV. Suggest why. [1 mark] - ANSWER-to kill virus or to prevent virus spreading 2.2 Scientists produced a single plant that contained a TMV-resistant gene. Suggest how scientists can use this plant to produce many plants with the TMVresistant gene. [1 mark] - ANSWER-take (stem) cells from meristem or tissue culture 2.3 Some plants produce fruits which contain glucose. Describe how you would test for the presence of glucose in fruit. [2 marks] - ANSWER-heat mixture and add a few drops of Benedict's solution glucose turns solution blue to orange TMV can cause plants to produce less chlorophyll. This causes leaf discoloration. Explain why plants with TMV have stunted growth. [4 marks] - ANSWER-• less photosynthesis because of lack of chlorophyll • therefore less glucose made so • less energy released for growth • because glucose is needed for respiration and /or • therefore less amino acids / proteins / cellulose for growth • because glucose is needed for making amino acids / proteins / cellulose Written answer: Plants with TMV have stunted growth because there is a lack of chlorophyll therefore less glucose is made through photosynthesis. This means there is less energy released for the growth of the plant because glucose is needed for respiration. 3.1 Describe two ways the body prevents the entry of microorganisms - ANSWER-any two from: • acid in stomach kills pathogens in food • skin forms a barrier / produces antimicrobial secretions • hairs in the nose trap (particles which may contain) pathogens • trachea / bronchi has mucus which traps pathogens or bronchi have cilia which waft mucus to throat to be swallowed In 2014 the Ebola virus killed almost 8 000 people in Africa. Drug companies have developed a new drug to treat Ebola. Explain what testing must be done before this new drug can be used to treat people. [6 marks] - ANSWER-• pre-clinical trials of the new drug on cells / tissues / live animals to test toxicity, dosage and efficacy • clinical trials / test on healthy volunteers and patients at very low doses • so that you can monitor for safety / side effects • and only then do trials to find the optimum dosage and test for efficacy • double blind trial / use of placebo • which does not contain the new drug • random allocation of patients to groups • so no one knows who has placebo / the new drug • peer review of data • to help prevent false claims Written answer: First, there are pre-clinical trials of the new drug on cells or live-animals in order to test toxicity, dosage and efficiency of the drug. Then there are clinical trials on healthy volunteers and then patients of the illness but at very low doses, to monitor for side effects. Then there is a double blind trial in which there are samples of the real drug and samples of placebo or fake drugs. Then with random allocation, patients are put into groups. With this method, no one knows who has the real drug or the placebo, to avoid biased data. Then there is a peer review of the data, in order to help prevent false claims, before the finalised drug is released for public use. 4.1 Respiration transfers energy from glucose for muscle contraction. Describe how glucose from the small intestine is moved to a muscle cell. [2 marks] - ANSWER-glucose is absorbed by diffusion into the bloodstream then blood delivers glucose to muscles in capillaries Written answer: In the body, glucose from the small intestine is absorbed by diffusion into the bloodstream. Then the blood delivers glucose to muscles via blood capillaries. 4.2 What is the purpose of the liquid paraffin in Tube A? [1 mark] Tick one box. To prevent evaporation To stop air getting in To stop the temperature going up To stop water getting in - ANSWER-To stop air getting in 4.3 The indicator solution in Tube B shows changes in the concentration of carbon dioxide (CO2). The indicator is: • blue when the concentration of CO2 is very low • green when the concentration of CO2 is low • yellow when the concentration of CO2 is high What colour would you expect the indicator to be in Tube B during maximum rate of anaerobic respiration? [1 mark] Tick one box. Blue Green Yellow - ANSWER-yellow 4.4 Suggest how the ex