Understanding Vaccination and Disease Prevention

Unit 3 Infection Biology

Q1. Many diseases are caused by viruses. Children are given vaccines to protect them against viral disease. (a) Explain how vaccination protects a child against a viral disease. ....................................................................................................................... . ....................................................................................................................... . ....................................................................................................................... . ....................................................................................................................... . ....................................................................................................................... . ....................................................................................................................... . (3)

M1. (a) dead / inactive form of virus introduced into body 1 white blood cells stimulated to produce antibodies 1 correct antibodies rapidly made if the body is infected with the virus 1

b) In the 1990s many people thought that the MMR vaccine caused autism in some children. This is why the Japanese government stopped using the MMR vaccine. The graph gives information about the percentage of Japanese children who developed autism during the 1990s. The data in the graph support the view that there is no link between MMR vaccination and autism. Explain why. ................................................................................................. ................................................................................................. ................................................................................................. (4)

(b) the percentage of children vaccinated fell to zero in 1995 1 but the number of children developing autism rose and fell during the period when % vaccinations was falling 1 number of children developing autism peaked after MMR vaccination had ceased 1 which suggests that something other than MMR vaccination was causing autism 1

Q2. Scientists at a drug company developed a new pain-killing drug, drug X. (a) Painkillers do not cure infectious diseases. Why? ....................................................................................................................... . (1)

M2. (a) dont kill pathogens / bacteria / viruses / microbes / microorganisms allow don t contain antibiotics ignore antibodies / attack / fight allow only treat symptoms / pain ignore kill disease / germs 1

(b) The scientists compared drug X with two other pain-killing drugs, drug A and drug B. In their investigation the scientists: chose 600 volunteers. The volunteers were all in pain gave 200 of the volunteers a standard dose of drug A gave 200 of the volunteers a standard dose of drug B gave 200 of the volunteers a standard dose of drug X. Over the next seven hours the volunteers recorded how much pain they felt. To get valid results the three groups of volunteers should be matched for as many factors as possible. Suggest two of the factors that should be matched. ....................................................................................................................... . ....................................................................................................................... . (2)

b) any two from: age gender extent / severity of pain or how long had pain before trial type of pain / illness / site of pain accept the pain for 1 mark, if neither extent or type given ignore pain threshold (body) mass / weight / height allow body size / physique other medical issues / drugs taken / health / fitness ethnicity 2

c) The graph shows the results of the investigation. (i) How much pain did the volunteers still feel, four hours after taking drug A? (iii) Give two advantages of taking drug B and not drug A. ................................................................. ....................................................... ................................................................. ....................................................... (2) ............................................................ percent (1) (ii) Give one advantage of taking drug A and not drug B. .............................................................................................................. .......... .............................................................................................................. .......... (1)

(c) (i) 75 ignore calculations / % 1 (ii) faster pain relief / decrease allow pain relief sooner or it works quicker or more pain relief at start / in first 1 / 1 hours 1 (iii) decrease of pain higher / more ignore more effective unless qualified by time > 1 hoursallow effect lasts longer 1 decrease of pain is longer lasting 1

(d) Drug X is much more expensive than both drug A and drug B. A pharmacist advised a customer that it would be just as good to take drug A and drug B together instead of drug X. Do you agree with the pharmacist s advice? Give reasons for your answer. ....................................................................................................................... . ....................................................................................................................... . ....................................................................................................................... . ....................................................................................................................... . (3)

(d) any three from: ignore yes or no (Yes because) rapid pain relief (from A) long lasting pain relief (from B) and it costs less the sum of the pain relief (from A + B) is greater (than X) (No because) drug X gives more pain relief (A + B / they ) might interact with each other could result in overdose could be more / new side effects if neither points gained allow (more) dangerous 3

Q3.In 2014 there was an outbreak of Ebola virus disease (EVD) in Africa. At the time of the outbreak there were: no drugs to treat the disease no vaccines to prevent infection. (a) By March 2015 there were an estimated 9 850 deaths worldwide from EVD. The number of deaths is an estimate. Suggest why it is an estimate rather than an exact number. ....................................................................................................................... . ....................................................................................................................... . (1)

any one from: not all deaths recorded not all causes of deaths recorded allow cause may not be known 1

(b) Why were antibiotics not used to treat EVD? ....................................................................................................................... . ....................................................................................................................... . ....................................................................................................................... . (1)

(b) antibiotics do not kill viruses allow antibiotics only kill bacteria 1

(c) After the outbreak began, drug companies started to develop drugs and vaccines for EVD. A drug has to be thoroughly tested and trialled before it is licensed for use. Testing, trialling and licensing new drugs usually takes several years. Draw one line from each word about drug testing to the definition of the word. Word about drug testing Definition Dose Side effects making the person ill The concentration of the drug to be used and how often the drug should be given Efficacy Whether the drug works to treat the illness Toxicity (2)

(c) all correct for 2 marks 1 or 2 correct for 1 mark 2

(d) The results of drug testing and drug trials are studied in detail by other scientists. Only then can the results be published by the drug company. Suggest one reason why the results are studied by other scientists. ....................................................................................................................... . ....................................................................................................................... . (1)

(d) any one from: to prevent false claims to make sure the conclusions are correct / valid to avoid bias 1

e) The number of deaths from EVD continued to increase. The World Health Organization (WHO) decided it was ethical to use unlicensed drugs. The WHO said unlicensed drugs could only be given to people who gave their permission. Also, any results had to be shared with other researchers and drug companies. Some vaccines had shown positive results in animal testing, but the vaccines had not been tested and trialled in humans. The supplies of the vaccine were low. At first the vaccines were only used for health workers. How would the use of a vaccine reduce the spread of EVD? ....................................................................................................................... . ....................................................................................................................... . (2)

(e) some people would be immune to EVD allow those vaccinated would not contract the disease 1 if less people (in a population) have EVD less chance of it being passed on 1

(f) Evaluate the use of unlicensed drugs and vaccines during the EVD outbreak.Give a conclusion. ....................................................................................................................... . ....................................................................................................................... . ....................................................................................................................... . (6)

) Level 3 (56 marks): A detailed and coherent evaluation is provided which considers a range of arguments for and against the use of unlicensed drugs and comes to a conclusion consistent with the reasoning. pros might save some lives vaccine could reduce chance of future outbreaks patient made aware of risk and agreed to use of drug sharing of results could speed up development of effective vaccines / drugs used mainly for health workers who were risking their lives to help cons could be dangerous or vaccine could harm a healthy person goes against legislation / laws governing drug development might set a precedent for other drugs not to be fully tested unfair as not available to the African people a justified conclusion 6

Q4.Bacteria and viruses can reproduce quickly inside the body and make us feel ill. These organisms may cause symptoms such as a high body temperature. (a) How do bacteria and viruses make us feel ill? ....................................................................................................................... ...... ....................................................................................................................... ...... (1)

.(a) (bacteria and viruses produce) toxins allow poisons allow damage body cells

c) The childrens body temperatures were measured before any medicine was given and every hour after treatment started. The mean body temperatures for each of the three groups are shown in the figure below. Time in hours (i) What was the difference in mean body temperature after 4 hours between the group taking paracetamol only and the group taking ibuprofen only? .............................................................................................................. ..... .............................. C (1) (ii) How many more hours did the mean body temperature stay normal or below normal, when taking both paracetamol and ibuprofen compared to taking ibuprofen only? .............................................................................................................. ..... .............................. hours (1)

(c) (i) 1.2 (C) 1 (ii) 3 (hours) 1

(d) Doctors and nurses usually advise parents to give ibuprofen to children with a high body temperature. Complete the sentences to suggest reasons why giving only ibuprofen might be better than giving only paracetamol or a combination of paracetamol and ibuprofen. You should use information from the table and the figure. (i) Giving ibuprofen might be better than giving paracetamol because ........ .............................................................................................................. ..... .............................................................................................................. ..... ii) Giving only ibuprofen might be better than giving a combination of paracetamol and ibuprofen because .................................................................................... .............................................................................................................. ..... .............................................................................................................. ..... .............................................................................................................. ..... (2) .............................................................................................................. ..... .............................................................................................................. ..... .............................................................................................................. ..... (2)

(d) (i) (Paracetamol) any two from: ibuprofen reduces body temperature faster ibuprofen reduces temperature more ibuprofen doesn t need to be taken as often ibuprofen keeps body temperature lower / normal / 37 C for longer allow works faster 2 (ii) (Paracetamol + ibuprofen) any two from: body temperature decreases at a similar rate allow ibuprofen works (almost) as fast ibuprofen maintained body temperature close to normal / 37 C allow ibuprofen maintained normal body temperature almost as long allow doesn t make temperature drop below normal as long (better to) take fewer drugs allow less chance of overdose / giving too much allow (better to) take drugs less frequently easier to administer allow less chance of missing doses / taking at the wrong time 2

Q5.The parts of the blood can be separated from each other by spinning the blood in a centrifuge. The image below below shows the separated parts of a 10 cm3 blood sample. (a) Calculate the percentage of the blood that is made up of plasma. ....................................................................................................................... . ....................................................................................................................... . Answer = .............................. % (2) (b) Name three chemical substances transported by the plasma. 1..................................................................................................................... ... 2..................................................................................................................... ... 3..................................................................................................................... ... (3)

(a) 55% 2 marks for correct answer alone accept 54 56 5.5 / 10 100 alone gains 1 mark 2 (b) any three from: amino acids antibodies antitoxins carbon dioxide cholesterol enzymes fatty acid glucose glycerol hormones / named hormones ions / named ions proteins urea vitamins water. ignore blood cells and platelets ignore oxygen max 1 named example of each for ions and hormones allow minerals

(c) In this question you will be assessed on using good English, organising information clearly and using specialist terms where appropriate. White blood cells are part of the immune system. White blood cells help the body to defend itself against pathogens. Describe how pathogens cause infections and describe how the immune system defends the body against these pathogens. ....................................................................................................................... . ....................................................................................................................... . (6)

Level 3 (5 6 marks) There is a good description of pathogens and the immune response with very few errors or omissions. Examples of biology points made in the response: bacteria and viruses are pathogens credit any ref to bacteria and viruses they reproduce rapidly inside the body bacteria may produce poisons / toxins (that make us feel ill) viruses live (and reproduce) inside cells (causing damage). white blood cells help to defend against pathogens by: ingesting pathogens / bacteria / (cells containing) viruses credit engulf / digest / phagocytosis to destroy (particular) pathogen / bacteria / viruses producing antibodies to destroy particular / specific pathogens producing antitoxins to counteract toxins (released by pathogens) credit memory cells / correct description this leads to immunity from that pathogen. 6

Q6. People can be immunised against a pathogen by injecting them with a vaccine. (a) What does a vaccine contain? ............................................................................................................... ............................................................................................................... (1)

. (a) dead / inactive form of pathogen / microorganism / bacterium / virus ignore disease (for organism) ignore toxins / antibodies 1

(b) A person was injected with a vaccine. A few weeks later the person was exposed to the pathogen they had been immunised against. The graph shows how the concentration of antibodies in the blood changed after injection of the vaccine and after exposure to the pathogen. (i) Describe in detail the differences between antibody production after the injection of the vaccine and after the person was exposed to the pathogen. .............................................................................................................. . .............................................................................................................. . (3) (ii) Suggest an explanation for the differences you have described in part (b)(i). .............................................................................................................. . .............................................................................................................. . .............................................................................................................. . (3)

(b) (i) any three from: (after exposure): greater number of antibodies produced / higher concentration Science Assessment- Higher antibodies stay (in higher concentration) for longer antibodies produced quicker (ii) white cells quantitative, eg 9 times higher / 0.8 to 7.2 scores 2 marks for increased to 9 times higher / from 0.8 to 7.2 allow lymphocytes / leucocytes do not accept phagocytes / macrophage 1 3 have had previous exposure to pathogen / recognise pathogen on re-entry /familiar with pathogen / reference to memory cells ignore knows how to kill pathogen ignore live pathogen introduced on exposure 1 therefore antibodies produced (more) rapidly this marking point dependent on previous marking point 1 [7]