Q1. (a) Scientists who investigate disease may look at risk factors. What is a risk factor? (1)

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1 Q. (a) Scientists who investigate disease may look at risk factors. What is a risk factor? () Scientists investigated the link between pollution from vehicle exhausts and the number of cases of asthma. Between 976 and 996, the scientists recorded changes in the following the concentration in the air of substances from vehicle exhausts the number of cases of asthma. The graph shows their results (b) Between which years on the graph was there (i) a positive correlation between the number of cases of asthma and the concentration in the air of substances from vehicle exhausts () (ii) a negative correlation between the number of cases of asthma and the concentration in the air of substances from vehicle exhausts? () Page of 7

2 (c) The scientists concluded that substances in the air from vehicle exhausts did not cause the increase in asthma between 976 and 980. Explain why (Extra space) (3) (Total 6 marks) Q. A doctor measured the volume of air in the lungs of two people over a period of 7 seconds. Both people were resting. One person was healthy. The other had emphysema. The results are shown in the table. Times / s Volume of air in lungs / dm 3 Person A Person B (a) The two people were breathing out during the time shown. What evidence in the table supports this statement? () Page of 7

3 (b) Calculate the rate at which person A breathed air out of his lungs between 0 and 3 seconds. Show your working. Answer... dm 3 s (c) Person B has emphysema. Give one piece of evidence from the table that shows this. () (d) Emphysema reduces the efficiency of gas exchange in the lungs. Explain why. (Extra space)... (4) (Total 8 marks) Page 3 of 7

4 Q3. (a) Pulmonary tuberculosis is a disease of the lungs. Describe the transmission and course of infection of pulmonary tuberculosis. (5) (b) Emphysema is another disease of the lungs. People with emphysema may feel weak and tired. Explain why. (5) (Total 0 marks) Page 4 of 7

5 Q4. Miner s lung is a disease caused by breathing in dust in coal mines. The dust causes the alveolar epithelium to become thicker. People with miner s lung have a lower concentration of oxygen in their blood than healthy people. (a) (i) Describe the path by which oxygen goes from an alveolus to the blood. (ii) Explain why people with miner s lung have a lower concentration of oxygen in their blood. () (b) In healthy lungs, a gradient is maintained between the concentration of oxygen in the alveoli and the concentration of oxygen in the lung capillaries. (i) Describe how ventilation helps to maintain this difference in oxygen concentration. (ii) Give one other way that helps to maintain the difference in oxygen concentration. () Page 5 of 7

6 (c) Scientists investigated the number of cases of miner s lung reported in Britain between 99 and 006. Coal mining in Britain had been dramatically reduced by 990. Some scientists concluded that the rise in reported cases of miner s lung after 99 shows that the disease takes a long time to develop. Evaluate this conclusion. (Total 8 marks) Page 6 of 7

7 Q5. The photographs show sections through alveoli of healthy lung tissue and lung tissue from a person with emphysema. Both photographs are at the same magnification. Biophoto Associates, Science Photolibrary (a) Give two differences that can be seen between the healthy lung tissue and the lung tissue from the person with emphysema (b) People with emphysema may find it difficult to climb stairs. Explain why. (3) (Total 5 marks) Page 7 of 7

8 Q6. The placebo effect describes the improvement in patients symptoms due to psychological effects. Scientists investigated the placebo effect in patients with asthma. They divided a large number of asthma patients into three groups,, and 3. Group inhaled a spray containing albuterol every day. Albuterol is a drug used to treat asthma. Group inhaled a placebo spray every day. This was identical to the spray given to group but it did not contain albuterol. Group 3 did not receive any spray treatment. (a) Describe one way the scientists could have allocated the patients to each group The scientists measured the forced expiratory volume (FEV ) of each patient at regular intervals. The forced expiratory volume (FEV ) is the volume of air forced out of the lungs in the first second when breathing out. The scientists recorded each patient s FEV before treatment started and after 60 days of treatment. They then calculated the mean increase in FEV for each group. Their results are shown in the graph. The bars show the standard deviation. Patient group Page 8 of 7

9 (b) What do the standard deviation bars suggest about the difference in the mean increase in FEV between Group and the other groups? Explain your answer (c) What do the data suggest about the placebo effect in this investigation? Explain your answer (d) On each occasion that a patient s FEV was measured, a doctor repeated the measurement several times. Explain why (e) All the patients continued with their normal treatment for asthma. The normal treatment was the same for all patients and its effects were short-lived. The patients were told to stop this treatment 4 hours before FEV measurements were taken. (i) Suggest why all the patients were allowed to continue with their normal asthma treatment in this investigation. () Page 9 of 7

10 (ii) Suggest why the patients were told to stop their normal asthma treatment 4 hours before their FEV measurements were taken. (f) After 60 days, the patients in each group were asked to give themselves an Improvement Score from 0-0 to show how much they felt their symptoms had improved. This was done before their FEV was measured. The scientists calculated the mean Improvement Score for each group. (i) The scientists concluded that the data obtained for the Improvement Scores were less reliable than the data obtained measuring FEV. Suggest why they concluded this. (ii) Group 3 reported the lowest mean Improvement Score. Suggest one explanation for this. (Total 5 marks) Page 0 of 7

11 M. (a) Something that increases chance / increases probability / makes it more likely; (b) (i) / to / and 980; (ii) / to / and 996; (c). Correlation does not mean that there is a causal relationship;. Do not accept casual. May be some other factor / named factor; 3. Associated with vehicles and asthma / producing rise in both; 4. (After 980) asthma continues to rise but exhaust concentration falls / negative correlation (after 980); 3 max [6] M. (a) Volume (of air in lungs) decreases; Accept: Results decrease (b) Correct answer.4;; Incorrect answer showing (vol. air breathed out =) / 4. (dm 3 ); (c) Reduced flow rates / less air breathed out / more air left in lungs (after breathing out); Insufficient: More air in lungs / high volume of air in lungs Page of 7

12 (d). Alveoli break down / collapse / rupture / fewer alveoli / larger alveoli or alveolar wall/epithelium walls thicken;. Reduced surface area / increased diffusion pathway; 3. (So) less diffusion; 4. Less elastin / elastic (tissue) / not recoiling / loss of elasticity / elastin permanently stretched; 5. Reduced flow rate / less air expelled; 6. So small / reduced diffusion or concentration gradient;. Neutral: Damage. Accept alveoli burst Less surface area for diffusion = marks (mark points and 3) 3. Accept diffusion less efficient. Reject diffusion of air 4. Elastic tissue must be in context of lungs. 6. Accept: Not maintaining a steep diffusion/concentration gradient. 4 max [8] M3. (a) (Bacteria transmitted in) droplets/aerosol; (Bacteria) engulfed/ingested by phagocytes/macrophages; 3 (Bacteria) encased in named structure e.g. wall/tubercle/granuloma/nodule; 4 (Bacteria) are dormant/not active/not replicating; 5 If immunosuppressed, bacteria activate/replicate/released; 6 Bacteria destroy alveoli/capillary/epithelial cells; 7 (Leads to) fibrosis/scar tissue/cavities/calcification; 8 (Damage) leads to less diffusion/less surface area/increases diffusion distance; 9 (Activation/damage allows bacteria) to enter blood/spreads (to other organs); Accept: TB/ it /the disease/air droplets Neutral: spread through the air/coughs/sneezes Reject: virus Neutral: destroyed by ; Accept: white blood cells 3 Neutral: bacteria contained 5 Accept: reference to HIV/old age/stress 7 Accept: fibrous tissue 8 Neutral: reduced gas exchange 8 Accept: reduced SA:VOL 5 max Page of 7

13 (b) Alveoli break down/collapse/rupture/walls thicken; Less surface area/increases diffusion distance/less diffusion; 3 Loss of elastin/elastic tissue/elastase involved; 4 (Alveoli/lungs) cannot recoil/spring back/have reduced elasticity/more difficult to expel air; 5 Reduced diffusion gradient/air not replenished/less air leaves lungs; 6 Less oxygen enters blood/tissues; 7 Less respiration/less energy released/less ATP produced; Neutral: alveoli damaged Accept: references to a lack of alpha--antitrypsin 3 This mark is for a structure. Accept: elastin permanently stretched 4 This mark is for a mechanism. Do not award reduced elasticity for 3. 4 Neutral: more difficult to inhale air 5 This mark is for a consequence Accept: reduced concentration gradient; Neutral: less air enters lungs 7 Q Reject: less energy produced /anaerobic respiration 7 Accept: less energy produced in the form of ATP /less oxygen for respiration 5 max [0] M4. (a) (i) Through alveolar epithelium; Through capillary epithelium/endothelium; Accept: Through lining/wall of alveolus and capillary for mark Accept: squamous epithelial cells for epithelium Neutral: alveolar endothelium Neutral: references to diffusion Q Correct use of terminology; (ii) (Thicker alveolar wall) no mark Neutral: less diffusion (So) Longer diffusion pathway/slower diffusion; Neutral: references to surface area Page 3 of 7

14 (b) (i) (In alveolus) Need the idea of air moving and oxygen concentration Brings in air containing a high(er) oxygen concentration; Neutral: reference to carbon dioxide concentration (ii) Removes air with a low(er) oxygen concentration; Circulation of blood/moving blood; Neutral: blood Neutral: short diffusion pathway (c) Long time between decrease in mining and increase in cases; Graph shows fluctuations; Correlation does not prove causation/there may be other causes of miner s lung; Improved diagnosis methods; Do not know number of cases/baseline before 990; Not all cases reported/not all individuals with miner s lung visit a doctor; Accept: correct use of figures from graph for the first marking point: e.g. cases do not increase until after 000/00-004/0 years later. max [8] M5. (a) Smaller number of alveoli; Larger air space per alveolus; Thicker walls; Q Accept converse for normal cells max (b) Less surface area of alveoli; Diffusion of gases / gas exchange reduced / less oxygen enters blood; Narrower bronchioles reduce gas flow; Loss of elasticity reduces gas flow / unable to ventilate efficiently; Lungs permanently inflated; Less energy available / less respiration possible for muscles; Q Award maximum of two marks if candidate suggests energy is used in respiration. 3 max [5] Page 4 of 7

15 M6. (a). Random; Random number generator = marks. Method e.g. number generator / number out of a hat; Same age = marks OR 3. Matched / all the same; 4. For e.g. age / sex; max (b). (Differences) are real / significant / not due to chance; It = the difference. (As) bars / SDs do not overlap;. Accept: standard errors do not overlap as told standard deviation in the question stem (c). No / slight (placebo) effect;. Group and 3 results are similar/the same / SDs / bars overlap;. Accept: other descriptions of Groups and 3. Accept: that Groups and 3 are not significantly different (d). (Allows) anomalies to be identified / ignored / effect of anomalies to be reduced / effect of variation in data to be minimised / concordant results; Accept: outliers instead of anomalies. Reject: idea of not recording anomalies / preventing anomalies from occurring. Accept: cancels out anomalies as bottom line response. (Makes) average / mean (more) reliable;. Q Neutral: makes the average / mean more accurate. Ignore: more reliable alone (e) (i). Unethical / unfair not to treat patients;. Dangerous / could cause an asthma attack; max (ii). Ensures normal treatment does not affect results / improvements are only due to the spray;. (As) normal treatment is short-lived / effective for less than 4 hours / (4h) is long enough for normal treatment to wear off; Page 5 of 7

16 (f) (i). (Improvement scores) are qualitative / subjective / rely on own judgement / different patients may assess symptoms differently; Accept: converse arguments for measuring FEV e.g. quantitative / objective patients cannot lie. Some patients may lie / exaggerate / want to please doctors;. Neutral: empirical evidence (ii). Not blind / patients knew they were not receiving treatment / patients did not receive treatment;. (So) more likely to underestimate / give lower scores / did not expect to improve / less improvement; [5] Page 6 of 7

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