AQA A-LEVEL BIOLOGY PAPER 3 2020 QP_verified_questions_2020.

AQA A-LEVEL BIOLOGY PAPER 3 2020 QP_verified_questions_2020. 0 1 S - The Marketplace for Revision Notes & Study Guides Downloaded by: ibrahim03naqvi | Distribution of this document is illegal S - The Marketplace for Revision Notes & Study Guides S - The Marketplace for Revision Notes & Study Guides 3 *03* Downloaded by: jessicaonyebuchi | Distribution of this document is illegal IB/M/Jun20/7402/3 2 3 9 Guppies with large brains are better at identifying predators. The scientists found that only female guppies with large brains were attracted to male guppies bright in colour. Do not write outside the box . Suggest and explain the advantage of this behaviour to the population of guppies. [3 marks] . Describe how the behaviour of female guppies could result in sympatric speciation. [3 marks] Turn over ► 0 1 0 1 S - The Marketplace for Revision Notes & Study Guides Downloaded by: ibrahim03naqvi | Distribution of this document is illegal S - The Marketplace for Revision Notes & Study Guides S - The Marketplace for Revision Notes & Study Guides 4 *04* Downloaded by: jessicaonyebuchi | Distribution of this document is illegal IB/M/Jun20/7402/3 1 In northern India, there is a conflict of interests between farmers of livestock (eg cows) and people trying to conserve ibex (a type of wild goat). When livestock are given extra food, their populations can grow too large and compete with ibex. Do not write outside the box . Name the type of competition between livestock and ibex. [1 mark] Livestock will outcompete ibex if they: • are in the same habitat • eat a similar diet. Scientists investigated this conflict of interests. Table 1 summarises some of the scientists’ findings. Table 1 Type of livestock Difference between livestock food and ibex food* Difference between livestock habitat and ibex habitat* Cow 1.0 1.5 Horse 0.5 0.0 Yak 0.0 2.0 * A score of 0.0 indicates that the food or habitat is the same. 0 2 0 2 S - The Marketplace for Revision Notes & Study Guides Downloaded by: ibrahim03naqvi | Distribution of this document is illegal S - The Marketplace for Revision Notes & Study Guides S - The Marketplace for Revision Notes & Study Guides 5 *05* Downloaded by: jessicaonyebuchi | Distribution of this document is illegal IB/M/Jun20/7402/3 . 2 There must be a balance between the need for conservation of the ibex and the need for farmers to keep livestock. Using all the information, suggest and explain three actions that the farmers could take to achieve this balance. Do not write outside the box [3 marks] 1 2 3 Turn over for the next question Turn over ► 0 2 4 S - The Marketplace for Revision Notes & Study Guides Downloaded by: ibrahim03naqvi | Distribution of this document is illegal S - The Marketplace for Revision Notes & Study Guides S - The Marketplace for Revision Notes & Study Guides 6 *06* Downloaded by: jessicaonyebuchi | Distribution of this document is illegal IB/M/Jun20/7402/3 1 2 3 In Europe, viruses have infected a large number of frogs of different species. The viruses are closely related and all belong to the Ranavirus group. Previously, the viruses infected only one species of frog. Do not write outside the box . Suggest and explain how the viruses became able to infect other species of frog. [2 marks] . Name two techniques the scientists may have used when analysing viral DNA to determine that the viruses were closely related. [1 mark] 1 2 . Determining the genome of the viruses could allow scientists to develop a vaccine. Explain how. [2 marks] 0 3 0 3 0 3 0 3 S - The Marketplace for Revision Notes & Study Guides Downloaded by: ibrahim03naqvi | Distribution of this document is illegal S - The Marketplace for Revision Notes & Study Guides S - The Marketplace for Revision Notes & Study Guides 7 IB/M/Jun20/7402/3 Distribution of this document is illegal . 4 Describe how the B lymphocytes of a frog would respond to vaccination against Ranavirus. You can assume that the B lymphocytes of a frog respond in the same way as B lymphocytes of a human. Do not write outside the box Do not include details of the cellular response in your answer. [3 marks] Turn over for the next question *07* Downloaded by: jessicaonyebuchi | Turn over ► 0 3 8 S - The Marketplace for Revision Notes & Study Guides Downloaded by: ibrahim03naqvi | Distribution of this document is illegal S - The Marketplace for Revision Notes & Study Guides S - The Marketplace for Revision Notes & Study Guides 8 IB/M/Jun20/7402/3 Distribution of this document is illegal 1 Table 2 shows information about two types of medicine. Table 2 Name of medicine Mass of medicine in one tablet / mg Maximum dose of medicine an adult is allowed Mass of sodium in one tablet / g Aspirin 300 0.6 g every 4 hours 0.15 Paracetamol 500 1.0 g every 6 hours 0.43 . A journalist studied the data in Table 2. She made the following suggestion. ‘If an adult takes the maximum number of tablets allowed for either of the medicines, then the person would have more than the RDA of sodium.’ The RDA (recommended daily allowance) of sodium for an adult human is 2.4 g per day. Is the journalist’s statement true for both of the medicines in Table 2? Use suitable calculations to support your answer. Do not write outside the box Show your working. [2 marks] *0 * 0 4 0 4 S - The Marketplace for Revision Notes & Study Guides Downloaded by: ibrahim03naqvi | Distribution of this document is illegal S - The Marketplace for Revision Notes & Study Guides S - The Marketplace for Revision Notes & Study Guides 9 IB/M/Jun20/7402/3 Distribution of this document is illegal Downloaded by: jessicaonyebuc hi | onyjessica1@g S - The Marketplace for Revision Notes & Study Guides Downloaded by: ibrahim03naqvi | Distribution of this document is illegal S - The Marketplace for Revision Notes & Study Guides S - The Marketplace for Revision Notes & Study Guides 10 *09* Downloaded by: jessicaonyebuchi | Distribution of this document is illegal IB/M/Jun20/7402/3 Doctors investigated the link between high sodium concentrations in medicines and hypertension (high blood pressure). They analysed medical records of patients. 1  of these patients had taken medicines containing high sodium concentrations. Each of these patients was paired with a patient from a control group. Do not write outside the box 0 4 . 2 Give two factors that should have been the same for each pair of patients and one factor that should have been different. [2 marks] Same factor 1 Same factor 2 Different factor 0 4 . 3 Doctors found: • 4.73% of the patients who had taken medicines containing high sodium concentrations suffered from hypertension • there were 7.18 times fewer control patients with hypertension. Calculate how many of the control patients had hypertension. Show your working. [2 marks] Answer patients Question 4 continues on the next page Turn over ► S - The Marketplace for Revision Notes & Study Guides Downloaded by: ibrahim03naqvi | Distribution of this document is illegal S - The Marketplace for Revision Notes & Study Guides S - The Marketplace for Revision Notes & Study Guides 11 *11* Downloaded by: jessicaonyebuchi | Distribution of this document is illegal IB/M/Jun20/7402/3 . 4 A high concentration of sodium in the blood can affect blood volume and cause hypertension. Use your knowledge of water potential to suggest how high sodium concentrations in the medicines taken could affect blood volume. Do not write outside the box [3 marks] 0 4 9 S - The Marketplace for Revision Notes & Study Guides Downloaded by: ibrahim03naqvi | Distribution of this document is illegal S - The Marketplace for Revision Notes & Study Guides S - The Marketplace for Revision Notes & Study Guides 12 *12* Downloaded by: jessicaonyebuchi | Distribution of this document is illegal IB/M/Jun20/7402/3 1 2 . In the UK in 2016, there were 525 048 deaths. Cancer caused 30.4% of all deaths. Throat cancer caused 5% of all deaths from cancer. Calculate the mean number of people who died of throat cancer per month in 2016. Do not write outside the box Show your working. [2 marks] Answer people per month Increased methylation of the promoter region of a tumour suppressor gene causes one type of human throat cancer. In this type of throat cancer, cancer cells are able to pass on the increased methylation to daughter cells. The methylation is caused by an enzyme called DNMT. Scientists have found that a chemical in green tea, called EGCG, is a competitive inhibitor of DNMT. EGCG enables daughter cells to produce messenger RNA (mRNA) from the tumour suppressor gene. . Suggest how EGCG allows the production of mRNA in daughter cells. [3 marks] Question 5 continues on the next page Turn over ► 0 5 0 5 S - The Marketplace for Revision Notes & Study Guides Downloaded by: ibrahim03naqvi | Distribution of this document is illegal S - The Marketplace for Revision Notes & Study Guides S - The Marketplace for Revision Notes & Study Guides 13 *13* Downloaded by: jessicaonyebuchi | Distribution of this document is illegal IB/M/Jun20/7402/3 3 The scientists investigated the effect of different amounts of EGCG on the growth rate of the throat cancer cells grown in vitro. Their results are shown in Figure 2. Figure 2 . A reporter who reviewed all of this work concluded that drinking green tea could be a cure for cancer. Do not write outside the box Suggest three reasons why his conclusion might not be valid. [3 marks] 1 2 3 0 5 8 S - The Marketplace for Revision Notes & Study Guides Downloaded by: ibrahim03naqvi | Distribution of this document is illegal S - The Marketplace for Revision Notes & Study Guides S - The Marketplace for Revision Notes & Study Guides 14 *14* Downloaded by: jessicaonyebuchi | Distribution of this document is illegal IB/M/Jun20/7402/3 Turn over for the next question DO NOT WRITE ON THIS PAGE ANSWER IN THE SPACES PROVIDED Do not write outside the box Turn over ► S - The Marketplace for Revision Notes & Study Guides Downloaded by: ibrahim03naqvi | Distribution of this document is illegal S - The Marketplace for Revision Notes & Study Guides S - The Marketplace for Revision Notes & Study Guides 15 *15* Downloaded by: jessicaonyebuchi | Distribution of this document is illegal IB/M/Jun20/7402/3 . 1 Describe the advantage of the Bohr effect during intense exercise.