When tobacco smoke is inhaled, chemicals such as nicotine and carbon monoxide enter the circulatory system through the gas exchange system. Tar builds up on the lining of the gas exchange system. Many people decide to give up smoking tobacco in order to improve their health.

Mark scheme

Marking points from the official mark scheme (May/June 2018). The mark or mark type is shown in brackets.

1. [3] three from:
2. any four named structures ;
3. mouth / nose / nostrils / nasal passages (count as one structure)
4. pharynx
5. larynx
6. trachea A windpipe
7. bronchus/bronchi
8. bronchiole / bronchioles
9. alveolus / alveoli / alveolar ducts / alveolar sacs
10. lungs
11. trachea, branches / divides, into (two main) bronchi;
12. correct sequence from bronchus (branching) to bronchioles to (end with) alveoli ;
13. further detail;; e.g. trachea has, C-shaped / incomplete rings, of cartilage bronchus has cartilage, plates / AW
14. diameters of gas exchange structures / respiratory tubes, decrease (towards alveoli)
15. [2] two from:
16. blood pressure, decreases / returns to normal;
17. platelets no longer sticky / risk of thrombosis decreases / risk of blood clotting decreases ;
18. endothelial repair (more likely to be) successful; A endothelium no longer damaged A decreased risk of, atheroma / atherosclerosis I less fatty deposits
19. heart rate, decreases / returns to normal; I heartbeat decreases
20. AVP; e.g. increased peripheral circulation / AW
21. blood vessels, not / less, constricted A less vasoconstriction A blood vessel (lumen) diameter increases / vasodilation occurs
22. [4] four from:
23. assume from point of view of giving up smoking unless stated otherwise
24. in lungs / at high partial pressures of oxygen
25. 1 (so) more oxygen taken up by haemoglobin / haemoglobin more saturated (with oxygen) / AW ; A haemoglobin has, increased / normal, affinity for oxygen
26. 2 before and after data / calculated difference in data, to support, from 10 kPa ;
27. 3 carbon monoxide no longer binding to haemoglobin / AW ; A carboxyhaemoglobin no longer forming / ora with ref. to smoking A haemoglobin has a higher affinity for CO than oxygen
28. 4 more (sites on) haemoglobin available to take up oxygen ;
29. in respiring tissues
30. 5 more oxygen dissociates from (oxy)haemoglobin / AW, at, lower partial pressures / below 4 kPa / in (respiring) tissues (after stopping); A haemoglobin less saturated (with oxygen) A haemoglobin has, less / decreased, affinity for oxygen
31. 6 before and after data / calculated difference in data, to support;
32. 7 ref. to increase in allosteric effect / regains ability for conformational change / AW ;
33. health benefits after stopping
34. 8 more / sufficient, oxygen to, transport/ deliver to, tissues / body
35. or
36. more oxygen to reach (respiring) tissues ; A less, tired / fatigued A more able to, do work / carry out exercise / be mobile R more energy unless qualified with link to aerobic respiration
37. [2] two from:
38. non-infectious
39. not from a pathogen; A bacteria / viruses / fungi for pathogens
40. A from lifestyle
41. A tar/carcinogen in smoke, causes mutation (in cells of lung)
42. cannot be passed onto another person / not transmissable / AW ;
43. disease
44. abnormal condition (affecting an organism) / condition that reduces the effectiveness of the functions of the organism / AW ;