INTERACTIVE MULTIPLE CHOICE QUESTIONS

1. INTERACTIVE MULTIPLE CHOICE QUESTIONS Diseases, causes, transmission and control The answers are provided. Explanations of why the alternatives are unsatisfactory are also offered

2. These multiple choice questions are similar to the ones set by the GCSE and IGCSE Examination Boards except that, in some cases, there may be more than one acceptable answer. For this reason, even if you select a correct answer at your first attempt, it is worth looking at all the alternatives (a) to see if there is a better answer and (b) to see why some of the alternatives are unacceptable.

3. Question 1 Which of the following is a transmissible disease? (a) Scurvy (b) Food poisoning (c) Diabetes (d) Cancer Question 2

4. No Scurvy is caused by a lack of vitamin C

5. Yes Food poisoning is caused either by one of a number of viruses or the bacteria Salmonella typhimurium or S. enteritidis. It is spread by contact with an infected person, or via food which has been handled by an infected person. The bacterial form may also come from animals, e.g. chickens, which carry the bacteria

6. No Diabetes is a metabolic disorder. It is caused either by insufficient production of insulin by the pancreas or by the failure of cells in the body to respond properly to insulin

7. No Cancer occurs when the normal control of cell division in a tissue fails

8. Question 2 Contagious disease is spread by … (a) infected droplets in exhaled air (b) mosquitoes or other biting, insects (c) contaminated food (d) direct or indirect contact with an infected person Question 3

9. No The term ‘contagious’ means that some form of contact is necessary to spread the disease

10. No Mosquitoes and other biting insects do spread diseases but not by mere contact. They need to insert their probosces into the infected person to pick up and transmit the disease

11. No Contaminated food can cause spread of disease but not by contagion. The food has to be ingested to cause the disease.

12. Yes The disease can be transmitted by direct contact with an infected person or by contact with some item used by that person, e.g a towel. Tinea is spread in this way

13. Question 3 Which of the following are sexually transmitted diseases? (a) Typhoid fever (b) Syphilis (c) Cholera (d) HIV (AIDS) Question 4

14. No Typhoid is transmitted by infected water or food

15. Yes Syphilis is spread by sexual intercourse with an infected person. Rarely it can be passed from an infected woman to her offspring. Syphilis can be treated by a course of injections with an antibiotic

16. No Cholera is an intestinal disease spread by contaminated food or water

17. Yes HIV (Human Immunodeficiency Virus) is spread by sexual contact with an infected person. It may also be transmitted unwittingly by the use of contaminated syringe needles. If untreated, HIV can cause AIDS (Acquired Immune Deficiency Syndrome)

18. Question 4 To reduce the chances of spreading disease, it is important to wash the hands … (a) frequently (b) before handling food (c) after handling food (d) after visiting the lavatory Question 5

19. No Although frequent hand-washing may reduce the chances of disease, unless it takes place at specific times it is not effective

20. Yes Intestinal diseases such as food poisoning or typhoid can be spread if food is contaminated by hands which carry disease organisms such as Salmonella

21. No If the food-handler’s hands are contaminated, the harm has been done while handling the food. Washing at this stage might be desirable but it will not reduce the spread of infection.

22. Yes After visiting the lavatory, there is the possibility that the fingers may have become contaminated by bacteria present in the faeces. Thorough hand-washing at this stage greatly reduces the chances of the bacteria contaminating food or objects such as door handles

23. Question 5 The chances of catching a sexually transmitted disease are greatly reduced if … (a) the man uses a condom (b) the couple keep themselves clean (c) the woman is on ‘the pill’ (d) the partners are ‘faithful’ to each other Question 6

24. Yes The condom prevents direct contact between the penis and vagina and also retains the semen. Viruses and bacteria cannot therefore be transmitted from one partner to the other

25. No Cleanliness is desirable but cannot prevent the spread of infection.

26. No The contraceptive pill may reduce the chances of conception but it can have no influence on the transmission of disease

27. Yes If both partners are free from disease to start with, so long as they remain ‘faithful’ to each other, there is no chance of contracting a sexually transmitted disease.

28. Question 6 The blood system combats infection by producing … (a) antibodies (b) antigens (c) antibiotics (d) antiseptics Question 7

29. Yes Antibodies are chemicals (immunoglobulins) produced by certain of the white cells in the blood. They neutralise or destroy foreign substances in the blood such as bacteria or their products.

30. No Antigens are foreign substances such as bacteria or their toxins in the blood, which provoke an immune reaction.

31. No Antibiotics are chemicals made by fungi or related organisms. They can be extracted and processed to be used as drugs to combat infection. Penicillin is an example of an antibiotic

32. No An antiseptic is an artificially produced substance which kills bacteria. It is used to sterilise instruments, surfaces or systems such as drains. Some forms can be used on the skin.

33. Question 7 A vaccine reduces the chances of getting a virus infection by … (a) killing the virus (b) making the bone marrow produce more white cells (c) prompting the body to produce antibodies (d) raising the body temperature Question 8

34. No A vaccine prompts an immune reaction which destroys viruses but does not itself ‘kill’ them.

35. No A virus infection may result in an increase in the population of white cells but this is not the primary function of a vaccine

36. Yes Vaccines provoke an immune reaction in the body which results in the production of antibodies against viruses and bacteria

37. No The body temperature may rise during an infection but this is not a function of the vaccine.

38. Question 8 If you have a wound contaminated by soil you may be given an anti-tetanus injection. The injection will contain anti-tetanus antibodies. This is an example of … (a) passive immunity (b) active immunity (c) artificial immunity (d) drug therapy Question 9

39. Yes It is passive immuity because the antibodies have not been produced by your own body but from another organism, e.g. a genetically engineered bacterium

40. No Active immunity results from the production of antibodies by your own immune system

41. No Artificial immunity is produced by injecting the body with a harmless form of the infective agent or its products. The body produces antibodies to the antigens and is stimulated to do so when when the real infective agent enters the body

42. No Drug therapy is used in order to cure rather than to prevent a disease

43. Question 9 Malaria is spread by … (a) exhaled droplets (b) houseflies (c) contact with an infected person (d) mosquitoes Question 10

44. No Many diseases are spread by droplet infection but not malaria

45. No Houseflies do spread diseases such as typhoid and cholera but they do so by contaminating food. They do not suck blood and so cannot transmit malaria

46. No Malaria is not a contagious disease

47. Yes Mosquitoes are blood-sucking insects. If they suck blood from an infected person, they pick up the malarial parasite which may then be transmitted to the next person to be bitten

48. Question 10 Which of the following are water-borne diseases ? (a) Influenza (b) Cholera (c) Typhoid (d) Tuberculosis

49. No Influenza is mostly transmitted via air-borne droplets or by contact with infected persons or objects

50. Yes Cholera is transmitted by contaminated water which contains bacteria from the faeces of infected persons. It is most likely to happen after a natural disaster which disables the sewage system