GCSE BITESIZE Examinations

Transcription

1 GCSE BITESIZE Examinations General Certificate of Secondary Education AQA SCIENCE A Unit Biology B1a AQA BIOLOGY Unit Biology B1a BLY1A (Human Biology) (Human Biology) HIGHER TIER Specimen Paper Time allowed: 30 minutes Maximum marks: 36 Instructions Answer all of the questions for the Tier you are attempting. Record your answers on a separate answer sheet only. Do all rough work in this book - not on your answer sheet. Advice Do not choose more responses than you are asked to. You will lose marks if you do. 1

2 HIGHER TIER SECTION ONE Questions ONE to FIVE In these questions, match the letters A, B, C and D with the numbers 1-4. Use each answer only once. Mark your choice on the answer sheet. QUESTION ONE This question is about drugs. Match drugs A, B, C and D with the numbers 1-4 in the sentences. A B C D alcohol cannabis painkillers statins Drugs are chemicals which alter the way the body works. Some drugs are used medically. Patients with high cholesterol levels are often prescribed 1. Patients with a bacterial or viral infection often take 2 to relieve the symptoms. However, some drugs are harmful. One widely consumed drug that can damage the liver and brain is 3. Another harmful drug that has been linked to mental illness, and can lead to people using harder drugs, is 4. 2

3 QUESTION TWO Diseases related to diet are on the increase in the Western world. Match diseases A, B, C and D with the numbers 1-4 in the table. A B C D Heart disease Diabetes Arthritis High blood pressure Description of the disease 1 Disease in which joints between bones wear down 2 Disease which is related to obesity and high salt intake 3 Disease caused by too much cholesterol in the blood 4 Disease in which the body becomes unable to control the blood sugar level 3

4 SECTION TWO Questions THREE to NINE Each of these questions has four parts. In each part, choose only one answer. Mark your choices on the answer sheet. QUESTION THREE An investigation was carried out to determine which antibiotic was most effective at killing a species of bacteria. The bacteria were spread onto an agar plate. Then four discs soaked with different antibiotics were placed on the surface of the agar. The plates were incubated for 48 hours to allow the bacteria to reproduce. The diagram below shows the results. The grey areas represent areas where the bacteria grew. The white areas represent areas where the bacteria did not grow. 4

5 3A The independent variable in this investigation was the type of antibiotic. What kind of variable is this? 1 Continuous variable 2 Discrete variable 3 Ordered variable 4 Categoric variable 3B The results from this investigation would be best displayed using... 1 a scattergram. 2 a line graph. 3 a bar chart. 4 a pie chart. 3C Using the information in the diagram, which antibiotic was most effective at killing the bacteria? 1 tetracycline 2 ampicillin 3 penicillin 4 streptomycin 3D Strains of the bacterium Staphylococcus aureus have developed which are resistant to several types of antibiotic. Scientists have named these strains MRSA. These strains have developed as a result of... 1 natural selection. 2 selective breeding. 3 natural immunity. 4 dirty conditions in hospitals. 5

6 QUESTION FOUR Any new medical drug or procedure has to undergo extensive clinical trials. The diagram below shows the stages involved in drug testing in the UK: 4A During human testing, why is the drug tested on healthy volunteers first? 1 To test how good the drug is at curing people. 2 To test the safety of the drug. 3 To test the long-term effects of the drug. 4 To compare the drug against other drugs on the market. 6

7 The drug varenicline has been developed to assist smokers in giving up. Following safety testing, it was clinically trialled to compare how well it worked against another anti-smoking drug called bupropion, and a placebo (sugar pill). Scientists recorded the percentage of volunteers who stopped smoking over three time intervals (12 weeks, 24 weeks and 52 weeks). The results are shown in the table below: Tablet taken Number of people Percentage in each group that had stopped smoking given tablet After 12 After 24 weeks After 52 weeks weeks varenicline bupropion placebo B Using the information in the diagram and the table to assist you, at which stage of the drug-testing procedure is this study likely to have taken place? 1 Laboratory stage 2 Phase 1 3 Phase 3 4 Phase 4 4C Why did the scientists give some of the volunteers a placebo (sugar pill)? 1 To show that the patients could not give up on their own. 2 To see the effects that sugar had on the obesity of the volunteers. 3 To make varenicline appear more effective than it is. 4 To act as a control group which the effectiveness of the varenicline could be compared against. 7

8 4D The scientists who collected the results deliberately did not know whether the patient was taking the drug or the placebo tablet, as the tablets were prepared by a different group of scientists. This was done because 1 the scientists taking the results did not have the expertise to prepare the tablets. 2 it prevented the scientists who took the samples from influencing the results. 3 it eliminated systematic error in collecting the results. 4 it spread the workload for the scientists involved in the drug trial. 8

9 QUESTION FIVE This question is about the menstrual cycle. 5A The menstrual cycle is regulated by hormones. Which row of the table shows the correct site where each of these hormones is produced? Site at which FSH is produced Site at which oestrogen is produced Site at which LH is produced Pituitary gland Ovaries Pituitary gland Pituitary gland Pituitary gland Ovaries Womb Ovaries Pituitary gland Pituitary gland Ovaries Ovaries 5B What is the role of the hormone FSH? 1 Causes the womb lining to become thicker 2 Stops the production of LH 3 Causes an egg to mature in an ovary 4 Causes the release of an egg from an ovary 9

10 Knowledge of the hormones which regulate the menstrual cycle can be used by scientists to increase or reduce a woman s fertility. 5C One type of female contraceptive pill contains the hormone oestrogen. Why would taking oestrogen on a daily basis prevent pregnancy? 1 It would prevent the woman from having a period. 2 It would inhibit any eggs from maturing. 3 It would prevent the release of eggs from the ovaries. 4 It would kill sperm cells, thereby preventing the sperm from fertilising the egg. 5D In vitro fertilisation (IVF) has helped many infertile couples to have children. In this technique, scientists inject hormones to allow them to harvest several of the woman s eggs, which they fertilise in a lab using sperm from the man. However, some people object to the ethics of using IVF to assist infertile couples. Which of these is a valid ethical objection? 1 The baby is often born with abnormalities. 2 Spare embryos are often frozen, and may eventually be disposed of. 3 The use of this technology is causing rapid growth in the human population. 4 IVF costs the NHS large amounts of money. 10

11 QUESTION SIX The diagram below shows the parts of the nervous system involved in a reflex action: 6A Which part of this diagram represents a synapse? 1 A 2 C 3 D 4 F 6B Which row in the table below shows the correct position of the neurones involved in a reflex action? Relay neurone Sensory neurone Motor neurone 1 C B E 2 B E C 3 B C E 4 E B C 11

12 6C If a person touches a hot object, the reflex response is for their arm to move away from it. The pathway of neurones which link the receptors and the arm muscle is approximately 1.6 metres long. Assuming that a nerve impulse travelled at 100 metres per second, it should take seconds for an impulse to travel this distance. In reality, the reflex action can take up to 0.5 seconds to produce a response. Which of these statements is not a plausible explanation for this? 1 The brain needs time to coordinate an appropriate response. 2 It takes time for the synapse to produce chemicals. 3 Transmission across the synapses is slower than along the neurones. 4 It takes time for the muscle to contract in response to an electrical impulse. 6D In addition to the nervous system, hormones are also used to coordinate processes within the body. Hormones are released by 1 receptors. 2 organs. 3 the blood. 4 glands. 12

13 QUESTION SEVEN During the first half of the 20th century, death rates from lung cancer showed an increase year upon year. In 1950, this prompted two British scientists, Sir Richard Doll and Sir Austin Bradford Hill, to investigate the cause of this increase. 7A At first they thought carcinogenic chemicals from motor car fumes and road tarmac were responsible for the increase. This was 1 an observation. 2 a hypothesis. 3 a theory. 4 a conclusion. They initially surveyed 700 hospital patients who were suffering from lung cancer and found that the common factor linking them was smoking. This led them to carry out a much more extensive study of 40,000 doctors over a four-year period, collecting information on how many of them smoked, and how many of them died from lung cancer. When analysing their results, they represented the general lung cancer death rate among men as 100%, and represented the death rates from lung cancer among different groups of smokers/non-smokers as percentage comparisons to this 100% figure. Their results are shown in the table below: Amount of tobacco smoked per day in g Percentage death rate from lung cancer compared with the general percentage death rate from lung cancer among all males 0 (Non-smokers) 9% 1-14 (Light smokers) 58% (Moderate smokers) 106% 25 or more (Heavy smokers) 205% 13

14 7B What is the increase in risk of dying from lung cancer for males who smoke heavily, compared with non-smokers? 1 Approximately twice as great 2 Approximately ten times greater 3 Approximately 20 times greater 4 Approximately 195 times greater 7C Why did they carry out such a large study of 40,000 doctors? 1 To make their data more accurate. 2 To make their data more precise. 3 To make their data more reliable. 4 To make their data more sensitive. 7D After his work was published, Sir Richard Doll worked for many cancer research organisations. During this time, he was also paid as a consultant by many chemical companies to advise them on chemicals and analyse data to see whether their chemicals were linked to cancers. These companies are likely to have sought his help because 1 his background made him the only scientist qualified to analyse the data. 2 he was an eminent scientist in his field, whose views were valued by other scientists. 3 they could manipulate him into passing chemicals which were unsafe. 4 he was well liked by the public, and this was good publicity for their products. 14

15 QUESTION EIGHT Vaccination involves exposing the white blood cells to an inactive or dead microorganism. The white cells then respond rapidly to any future re-infection by that microorganism. 8A For a vaccine to be effective in protecting a population from the disease, scientists state that 95 per cent of the population needs to receive the vaccine. Why would only vaccinating 95 per cent of people be enough to protect the whole population from a disease? 1 The antibodies made by the people who were vaccinated could be passed on to the remaining 5 per cent. 2 There would be insufficient susceptible people to spread the disease. 3 Medicines could be focused on treating the remaining 5 per cent. 4 The vaccine would eventually be passed to the next generation and spread. The graph below shows the number of cases of measles in England and Wales between 1940 and 2004, and the percentage of children who were vaccinated against measles after

16 8B What was the range in measles cases seen in the years before the first measles vaccination was introduced? 1 147,000 to 764, to to ,000 to 694,000 8C In 1998, a team of scientists led by Dr Andrew Wakefield published an article claiming that their data indicated a potential link between the combined measles, mumps and rubella (MMR) vaccine and a condition known as autism. This led to some parents not vaccinating their children. Between 1998 and 2001, by how much did the percentage of children that were vaccinated decrease? per cent 2 7 per cent 3 60 per cent 4 80 per cent 8D Flu vaccines, containing inactivated influenza virus, are available. However, they have not been as successful as vaccines such as the MMR vaccine at conferring long-term immunity to the disease. The reason why flu vaccination is not as effective at conferring long-term immunity is 1 The inactivated flu virus in the vaccine is not detected by white blood cells. 2 The viruses in the vaccine do not work because they have been inactivated. 3 The vaccine needs further development. 4 The influenza virus mutates frequently to produce new strains. 16

17 QUESTION NINE This question is about cholesterol. 9A Read the statements below: i) The amount of cholesterol in the blood depends on your diet only. ii) High-density lipoproteins (HDLs) are considered to be good cholesterol. iii) Excessive cholesterol in the blood can contribute to narrowing of the blood vessels. Which of the statements in the box above are correct? 1. i) and ii) 2. i) and iii) 3. ii) and iii) 4. i), ii) and iii) 17

18 In an investigation, 60 people had their normal diet replaced with a controlled diet that was high in foods containing either saturated, monounsaturated or polyunsaturated fats. The total LDL cholesterol and HDL cholesterol levels in the blood were taken before the start of the investigation, and after several weeks on the replacement diet. The change in LDL and HDL cholesterol levels in the blood was then measured. The graph below shows the results of this investigation: 9B How much higher were HDL cholesterol levels for the diet containing saturated fats, compared with the diet containing monounsaturated fats? 1 2 per cent 2 10 per cent 3 12 per cent 4 25 per cent 18

19 9C Which of these statements is a valid conclusion to draw from the investigation? 1 A diet that is high in saturated fats is best, as it increases the level of HDL cholesterol the most. 2 A diet that is high in polyunsaturated fats is best, as it lowers LDL cholesterol the most. 3 A diet that is high in saturated fats is best, as it increases the level of LDL cholesterol. 4 A diet that is high in monounsaturated fats is best, as it gives the best combination in terms of reducing LDL cholesterol while increasing HDL cholesterol. 9D In the experiment, some of the 60 people tested showed changes in their LDL and HDL cholesterol levels above or below the mean changes shown in the graph. Theses differences are likely to be due to 1 systematic error in how the scientists carried out the technique. 2 variation in the diet of the 60 volunteers. 3 the measuring equipment being incorrectly calibrated. 4 variation in inherited factors among the 60 volunteers. END OF QUESTIONS 19