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Transcript
Q1. (a) (i) Some diseases can be tackled by using antibiotics and vaccination. Explain fully why antibiotics cannot be used to cure viral diseases. .......................................................................................................................... .......................................................................................................................... .......................................................................................................................... .......................................................................................................................... (2) (ii) A recent study found that babies in 90 % of hospitals are infected with the MRSA bacterium. Explain how the MRSA bacterium has developed resistance to antibiotics. .......................................................................................................................... .......................................................................................................................... .......................................................................................................................... .......................................................................................................................... (2) (b) A person can be immunised against a disease by injecting them with an inactive form of a pathogen. Explain how this makes the person immune to the disease. ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... (3) (Total 7 marks) Q2. (a) Explain how diseases caused by bacteria are usually treated by doctors. ..................................................................................................................................... ..................................................................................................................................... (2) Page 1 of 28 (b) Explain, as fully as you can, how white blood cells protect us from disease. ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... (5) (Total 7 marks) Page 2 of 28 Q3. Read the passage about antibiotics. People do not always agree about the use of antibiotics in food production. If we put low doses of antibiotics in feed for animals such as cattle and sheep, it helps to produce high-quality, low-cost food. Antibiotics help to keep animals disease-free. They also help animals to grow. Animals get fatter quicker because they do not waste energy trying to overcome illness. The use of antibiotics in livestock feed means that there is a higher risk of antibiotic-resistant bacteria developing. The rapid reproduction of bacteria means there is always a chance that a population of bacteria will develop which is antibiotic-resistant. These could be dangerous to human health. (a) To gain full marks for this question you should write your ideas in good English. Put them into a sensible order and use the correct scientific words. Explain how a population of antibiotic-resistant bacteria might develop from non-resistant bacteria. .................................................................................................................................... .................................................................................................................................... .................................................................................................................................... .................................................................................................................................... .................................................................................................................................... .................................................................................................................................... (3) (b) Do you think that farmers should be allowed to put low doses of antibiotics in animal feed? Explain the reasons for your answer. .................................................................................................................................... .................................................................................................................................... .................................................................................................................................... .................................................................................................................................... (2) (Total 5 marks) Q4. Many diseases are caused by viruses. Children are given vaccines to protect them against viral disease. (a) Complete the following sentences. It is difficult to kill viruses inside the body because viruses ......................................................................................................... . A vaccine contains an ............................................... form of the virus. The vaccine stimulates the white blood cells to produce ............................. . (3) Page 3 of 28 (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. Page 4 of 28 The data in the graph support the view that there is no link between MMR vaccination and autism. Explain why. ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ (4) (Total 7 marks) Q5. Influenza is a disease caused by a virus. (a) Explain why it is difficult to treat diseases caused by viruses. ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... (2) Page 5 of 28 (b) In some years there are influenza epidemics. The graph shows the death rate in Liverpool during three influenza epidemics. (i) The population of Liverpool in 1951 was approximately 700 000. Calculate the approximate number of deaths from influenza in week 4 of the 1951 epidemic. Show clearly how you work out your answer. ........................................................................................................................... ........................................................................................................................... Number of deaths .............................. (2) (ii) In most years, the number of deaths from influenza in Liverpool is very low. Explain, in terms of the influenza virus and the body’s immune system, why there were large numbers of deaths in years such as 1918 and 1951. ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... (3) (Total 7 marks) Page 6 of 28 Q6. The influenza virus damages the cells lining the respiratory tract causing sore throats. Coughing and sneezing spread the virus. (a) Give the correct term for this method of spreading an infection. .................................................................................................................................... (1) (b) In an immunisation programme such as that for MMR (Measles, Mumps and Rubella), suggest why it is essential for a large proportion of the child population to be vaccinated in order to protect the few individuals who are unable to be vaccinated. .................................................................................................................................... .................................................................................................................................... (1) (c) In some modern influenza vaccines the protein surface sub-units are separated from the virus coat and used for the vaccine. This stimulates an effective immune response in the same way as inactive pathogens. (i) Explain how this immunity is produced in the body following vaccination, and how further illness from the same virus is prevented. ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... (4) (ii) This type of immunity resulting from an influenza injection is described as ..................................................... immunity. (1) Page 7 of 28 (d) The diagram shows the structure of an influenza virus. Influenza epidemics can arise because the nucleic acid of the virus frequently changes. This results in changes in the virus structure and so a new strain of the virus is formed. A person who has had influenza or who has been vaccinated may not be immune to the new strain. Explain why this is so, using the diagram of the influenza virus structure and your knowledge of immunity. .................................................................................................................................... .................................................................................................................................... .................................................................................................................................... .................................................................................................................................... .................................................................................................................................... .................................................................................................................................... (3) (Total 10 marks) Page 8 of 28 Q7. Read the following passage. ‘The immune system is the body’s defence force. It protects against infections which might enter the body. The potential invaders include bacteria and viruses. The two basic defences are cells and chemicals. The best known action of defence cells is the ingesting and killing of microbes. The best known chemical defence is the antibody - a protein 5 specially made to match with the surface of an invading microbe. Once covered with antibody, the microbe becomes easier to destroy. So how do the invaders ever win? Part of the answer is that the chemical defenders take some time to become effective. When the body is infected for the first time by a particular microbe, there is a race between the multiplying microbes and the multiplying 10 cells producing the antibody. Given time, the body usually wins; eventually enough antibodies are formed to overcome the invaders. But if the initial invasion force is large, or the immune system is weak, the battle may be lost.’ (a) (i) Which type of cells ingest and kill invading microbes? (lines 3 - 4) ........................................................................................................................... (1) (ii) Give two circumstances in which the initial invasion force might be very large (lines 11 - 12). 1 ........................................................................................................................ ........................................................................................................................... 2 ........................................................................................................................ ........................................................................................................................... (2) (iii) After being ingested, the microbes are digested in the cells. Briefly explain what happens to the proteins that the microbes contain. ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... (2) (b) Explain how bacteria cause disease once they get into the body. ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... (2) (c) Name a type of medicine that kills bacteria inside the body. ..................................................................................................................................... (1) Page 9 of 28 (d) People often risk first-time infection by a particular microbe while visiting other countries. People can be immunised against the disease that the microbe causes. Explain, as fully as you can, how immunisation works. ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... (3) (Total 11 marks) Q8. Reflex actions are rapid and automatic. (a) Name the following structures in a reflex action. (i) The structure that detects the stimulus. ........................................................................................................................... (1) (ii) The neurone that carries impulses to the central nervous system. ........................................................................................................................... (1) (iii) The neurone that carries impulses away from the central nervous system. ........................................................................................................................... (1) (iv) The structure that brings about the response. ........................................................................................................................... (1) (b) Describe what happens at a synapse when an impulse arrives. ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... (2) Page 10 of 28 (c) Some people have a condition in which information from the skin does not reach the brain. Explain why this is dangerous for the person. ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... (2) (Total 8 marks) Q9. Hormones are sometimes used to regulate human reproduction. (a) (i) What is a hormone? ........................................................................................................................... ........................................................................................................................... (1) (ii) How are hormones transported around the body? ........................................................................................................................... ........................................................................................................................... (1) Page 11 of 28 (b) Describe the benefits and possible problems that may result from the use of hormones to regulate human reproduction. You should refer to fertility drugs and contraceptives in your answer. To gain full marks in this question you should write your ideas in good English. Put them into a sensible order and use the correct scientific words. ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... (4) (Total 6 marks) Q10. This question is about the hormones that control the monthly cycle in women. Complete the sentences. Hormones control the monthly release of an egg from a woman’s ................................ . They also control the thickness of the lining of her .................................................... . Hormones that are given to women to stimulate the release of eggs are called .................................................... drugs. Hormones that are given to women to prevent the release of eggs are called oral .................................................... . (Total 4 marks) Page 12 of 28 Q11. A person accidentally touches a hot pan. Her hand automatically moves away from the pan. The diagram shows the structures involved in this action. (a) Describe fully how the structures shown in the diagram bring about this reflex action. ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ ........................................................................................................................ (6) (b) (i) The nerve pathway in this reflex action is about 1.5 metres in length. A nerve impulse travels at 75 m s–1. Use this information to calculate the time taken for this reflex action to occur. Show clearly how you work out your answer. ............................................................................................................... ............................................................................................................... Time intervals ....................................... s (2) Page 13 of 28 (ii) The actual time interval is longer than the interval you have calculated in part (i). Suggest an explanation for the difference. ............................................................................................................... ............................................................................................................... (1) (Total 9 marks) Q12. A woman’s fertility can be controlled by using hormones. (a) Some contraceptive pills contain oestrogen. Name the gland which produces oestrogen. ..................................................................................................................................... (1) Women are being encouraged to use longer-term methods of contraception to reduce their chances of having an unwanted pregnancy. The table summarises four long-term methods of contraception. Method What it is How it works How long does it last? Chances of getting pregnant Side effects Hormone implant Rod containing slow-release hormone inserted under the skin Stops ovaries releasing eggs 3 years Less than 1 in 1000 Acne in some women Hormone injection Injection that slowly releases hormone Stops ovaries releasing eggs 12 weeks Less than 4 in 1000 Weight gain in some women IUD Small plastic and copper coil placed in womb Stops fertilized eggs developing in womb 5–10 years Less than 20 in 1000 Heavier or more painful periods in some women IUS Plastic device containing slow-release hormone placed in womb Stops fertilized eggs developing in womb 5 years Less than 10 in 1000 Irregular periods in some women Page 14 of 28 (b) Which of the methods in the table is the most reliable? ..................................................................................................................................... (1) (c) What is the advantage of using long-term contraception methods instead of taking a contraceptive pill every day? ..................................................................................................................................... ..................................................................................................................................... (1) (d) The IUD is the least reliable of the contraceptive methods shown in the table. Use information from the table to suggest a reason for this. ..................................................................................................................................... ..................................................................................................................................... (1) (e) Some people have ethical objections to the use of an IUD or an IUS. Suggest one reason why people might object to their use. ..................................................................................................................................... ..................................................................................................................................... (1) (f) (i) Explain how the hormone in the implants prevents the ovary releasing eggs. .......................................................................................................................... .......................................................................................................................... .......................................................................................................................... .......................................................................................................................... (2) (ii) Hormones can also be used as ‘fertility drugs’. Explain how a fertility drug helps a woman to become pregnant. .......................................................................................................................... .......................................................................................................................... .......................................................................................................................... .......................................................................................................................... (2) (Total 9 marks) Page 15 of 28 Q13. The diagram shows how Dolly the sheep was cloned. (a) Name the type of cell division that occurs: (i) as the egg cell is produced; ............................................... (ii) as the fused cell begins to divide normally. ............................................... (2) (c) The diagram below shows the relationships between the glands and hormones that control the menstrual cycle of a woman. (i) Name: gland X; ............................................... hormone Y. ............................................... (2) Page 16 of 28 (ii) Give two effects of the hormone oestrogen on gland X. 1 ........................................................................................................................ ........................................................................................................................... 2 ........................................................................................................................ ........................................................................................................................... (2) (Total 6 marks) Q14. A woman wants to have a baby. She has been told that her body is not making and releasing eggs. However she has thousands of cells which could develop into them. A possible treatment is to give her a hormone called FSH. This hormone will start the development of these cells. Once the eggs have developed, explain what causes their release. ............................................................................................................................................... ............................................................................................................................................... ............................................................................................................................................... ............................................................................................................................................... ............................................................................................................................................... ............................................................................................................................................... (Total 4 marks) Page 17 of 28 M1. (a) (i) viruses live inside cells 1 viruses inaccessible to antibiotic allow drug / antibiotic (if used) would (have to) kill cell 1 (ii) mutation ignore mutation caused by antibiotic 1 natural selection or no longer recognised by antibiotics accept description of natural selection 1 (b) (stimulate) antibody production ignore antitoxin 1 (by) white cells 1 rapidly produce antibody on re-infection ignore antibodies remain in blood 1 [7] M2. (a) use antibiotics; or named one to kill bacteria; (not microbes) each for 1 mark 2 (b) some ingest/digest bacteria (not microbes) OWTTE some produce antibodies; which destroy bacteria/viruses; some produce antitoxins; which counteract poisons released by bacteria each for 1 mark 5 [7] Page 18 of 28 M3. (a) Quality of written communication The answer to this question requires ideas in good English in a sensible order with correct use of scientific terms. Quality of written communication should be considered in crediting points in the mark scheme idea of mutation or variation do not allow ‘bacteria get used to antibiotics’ or idea that antibiotics change the bacteria or ‘bacteria become immune’ or references to adaptation or evolution 1 (resistant cells) survive antibiotic 1 (resistant cells) breed 1 (b) EITHER (yes) keep animals disease free (1) so grow faster (1 mark) or live longer OR (no) resistant bacteria may develop (1) risk to human or animal health (1) allow bacteria become resistant / immune 2 [5] M4. (a) live inside cells 1 inactive 1 antibodies 1 (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 [7] Page 19 of 28 M5. (a) any two from • live inside / infect body cells • difficult for drugs to enter (body) cells / drug would kill (body) cell • antibiotics ineffective against viruses • viruses mutate frequently 2 (b) (i) 420 correct answer with or without working if answer incorrect evidence of ‘number of deaths’ × 7 or 60 seen gains 1 mark ignore 6 000 000 2 (ii) any three from: • virus / flu mutates • people no longer / not immune ignore resistance • white blood cells / memory cells / immune system do not recognise virus • relevant reference to antibodies / antigens • current vaccine ineffective or no vaccine available then or takes time to develop new vaccine allow no tamiflu / anti-viral drugs • conditions less hygienic / lack of hygiene • people in poor health (following world wars) allow people had ‘weak’ immune system 3 [7] M6. (a) droplet infection or aerosol infection do not accept airborne accept airborne droplets 1 (b) so there is no large group which could catch the infection/pass on the infection converse – if large numbers can’t pass it on the virus is less likely to reach those few who are susceptible 1 Page 20 of 28 (c) (i) any four of the following points:example of a 3 mark answer: Lymphocytes produce specific antibodies…... comment on specificity applied to antibodies or lymphocytes (recognition by) lymphocytes; (white cells) make antibodies; antibodies destroy/neutralise the virus/antigen/protein subunit; do not accept antibodies KILL viruses accept white blood cells replicate accept some white cells form memory cells/live a long time; accept subsequent infection results in very rapid antibody production; max 4 (ii) active; 1 (d) any three of the following points Structure change in: protein for binding to host cell; accept changes in surface proteins (of protein coat) spike containing enzyme; changes in antigen Fit: existing/circulating/old antibodies don’t match new virus strain shape/new antigen/new binding protein; Wrong antibodies: injection does not stimulate antibodies against all strains/different antigens; accept wrong antibodies for 1 mark max 3 [10] ## (a) (i) white blood cells for 1 mark 1 (ii) e.g. contact with infected person unhygienic conditions for 1 mark each 2 (iii) broken down, by enzymes into amino acids any 2 for 1 mark each 2 Page 21 of 28 (b) reproduce rapidly produce toxins for 1 mark each 2 (c) antibiotic or named for 1 mark 1 (d) mild or deal microbes introduced white cells produce antibodies which can destroy disease microbes idea of memory cells idea that injecting antibodies give immediate production any 3 for 1 mark each 3 [11] M8. (a) (i) receptor allow named receptor eg light receptor ignore sensory neurone allow sense organ / named sensory organ eg skin / eye 1 (ii) sensory (neurone) allow afferent 1 (iii) motor (neurone) allow efferent 1 (iv) effector / muscle / gland / named 1 (b) any two from: • impulse / information passes from one neurone to another or impulse / information passes across gap • chemical / transmitter involved • diffusion (across gap) 2 Page 22 of 28 (c) brain / person not aware of pain / stimulus / can’t feel allow brain/ person doesn’t know / realise / unable to coordinate ignore reflex ignore information 1 possibility of (permanent / serious) damage / eg burning ignore danger 1 [8] M9. (a) (i) any one from: • chemical messenger • chemical / substance released in one part to have effect elsewhere in body • chemical / substance which affects another / target organ / tissues / cells allow chemical from endocrine gland 1 (ii) in blood / circulatory system / any named part including plasma extra wrong answer would cancel example not red blood cells 1 (b) Quality of written communication: correct use of at least two relevant scientific terms spelt phonetically e.g. pregnancy, ovulation, FSH, oestrogen, progesterone, ovary, follicle, circulation, thrombosis, feminisation, sperm count, STD Q or Q 1 Page 23 of 28 any three from: Oral contraceptives: (benefit) • prevent (unwanted) pregnancy or prevent egg release • regulate menstrual cycle / periods (problems) • prolonged use may prevent later ovulation / cause infertility • named side-effect on female body e.g. circulatory problems / weight gain / nausea / headache / breast cancer / mood swings • increased promiscuity / increase in STD’s / STI’s • named side-effect on environment e.g. feminisation of fish or lowered sperm count in human males Fertility drugs: (benefit) • can enable woman to have children or to become pregnant or stimulates egg release (problem) • multiple births for full marks must score at least one re contraceptives and at least one re fertility drugs if unclear which type of hormone maximum 2 marks from 3 3 [6] Page 24 of 28 M10. ovaries accept ovary 1 womb accept uterus 1 fertility accept FSH do not accept fertilisation 1 contraceptive(s) allow birth control accept oestrogen or progesterone do not accept pill alone 1 [4] M11. (a) stimulus / heat detected by temperature receptors in skin 1 impulses travel along sensory neurone to spinal cord / CNS 1 chemical transmission across synapse 1 via relay neurone 1 impulses to muscle / effector via motor neurone 1 muscle / effector contracts, moving the hand away 1 (b) (i) 0.02 s correct answer gains 2 marks if answer incorrect, evidence of 1.5 / 75 gains 1 mark 2 (ii) impulse slowed down because of time taken for diffusion of the chemical across the synapse 1 [9] Page 25 of 28 M12. (a) ovary or ovaries 1 (b) (hormone) implant 1 (c) do not have to remember to take 1 (d) does not involve hormone allow coil may be dislodged or it is a mechanical method allow egg is fertilised / released allow not preventing egg fertilisation / release 1 (e) involves death of fertilised egg allow embryo / baby for fertilised egg or (regard) fertilised egg as human ignore against religion only allow fertilised egg is alive or stops fertilised egg developing ignore side effects 1 (f) (i) inhibit FSH (production) allow inhibits LH 1 so no eggs mature / develop / are produced allow (LH) stimulates egg release ignore progesterone 1 (ii) contains FSH allow contain LH 1 which causes egg to mature / develop / be produced allow (LH) stimulates egg release or in women whose FSH is low 1 [9] Page 26 of 28 M13. (a) (i) meiosis 1 (ii) mitosis 1 (c) (i) X pituitary 1 Y FSH 1 (ii) stimulates LH production 1 inhibits FSH production / production of Y 1 [6] M14. oestrogen produced gains 1 mark but N.B. sequence important here oestrogen produced by ovary gains 2 marks LH produced gains 1 mark but LH produced by pituitary gains 2 marks LH causes egg release for1 mark [4] Page 27 of 28 Page 28 of 28