10.1. Infectious diseases
A subsection of Biology, 9700, through 10. Infectious diseases
Listing 10 of 208 questions
Explain why tuberculosis (TB) is known as an infectious disease. Outline the role of antibiotics in the treatment of infectious diseases, such as TB. Tobacco smoking is a risk factor for a number of diseases. This means that it increases the risk of developing disease. In 2009, the World Health Organization (WHO) published a factsheet stating that tobacco smoking: • may be responsible for more than 20% of the new cases of TB globally • increases the risk of becoming infected and having active TB • increases the risk of dying from TB • is a risk factor for TB in all socioeconomic groups. Projects have been set up in a number of different countries to tackle this health problem. One project involves health workers encouraging TB patients to give up smoking. Suggest what epidemiological evidence would lead to the conclusion that tobacco smoking is a risk factor for TB. Suggest and explain how the effects of smoking can increase the risk of becoming infected with TB. Many smokers know that tobacco smoking is a risk factor for coronary heart disease, but continue to smoke. Some of these smokers have stated that they expect medical practitioners to cure them if they develop coronary heart disease. List two treatments used by medical practitioners to treat coronary heart disease. 1. 2.
9700_s13_qp_22
THEORY
2013
Paper 2, Variant 2
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Vibrio cholerae is a prokaryotic organism. shows the structure of a cell of V. cholerae. 3.0 +m G F E D C A B capsule Calculate the magnification of . Show your working and give your answer to the nearest whole number. magnification × Locate the structures in that apply to each of the features shown in Table 1.1. Complete Table 1.1 by writing the appropriate letter and the name of the structure. You must only give one letter in each case. You may use each letter once, more than once or not at all. The first answer has been completed for you. Table 1.1 feature identity name provides motility F flagellum stores genetic information partially permeable composed of murein site of translation State three structural features that are present in a mesophyll cell in a leaf that are not present in a prokaryotic cell such as that of V. cholerae. 1. 2. 3. Describe how V. cholerae is transmitted from an infected person to an uninfected person. It is important to know how pathogens are transmitted in order to develop effective control methods. Explain how this knowledge is used to control the spread of V. cholerae in the human population.
9700_s14_qp_21
THEORY
2014
Paper 2, Variant 1
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Table 4.1 shows some information about five infectious diseases. Table 4.1 infectious disease name of causative organismtype of causative organism main mode of transmission HIV/AIDS human immunodeficiency virus (Hvirus sexual contact cholera Vibrio cholerae ingestion of contaminated water and food tuberculosis Mycobacterium tuberculosis bacterium measles virus aerosol / droplet infection Plasmodium vivax or P. malariae or P. falciparum or P. ovale Complete Table 4.1. In 2011, the World Health Organization (WHO) published recommendations to help countries develop plans to prevent the spread of HIV. Discuss the factors that should be considered when making recommendations concerning the prevention of sexual transmission of HIV. HIV infects cells of the immune system, particularly helper T-lymphocytes (Th cells). HIV can infect both non-dividing and dividing helper T-lymphocytes, including memory cells. The onset of disease, which can occur many years later, coincides with a severely lowered primary and secondary immune response, owing to greatly reduced numbers of Th cells in the body. An infected Th cell can still carry out a normal cell cycle and divide to produce two cells. The following processes occur during one cell cycle: DNA replication mitosis growth cytokinesis List the processes in a correct sequence. 1. 2. 3. 4. Suggest and explain how the destruction of memory Th cells will contribute to a lowered secondary immune response.
9700_s14_qp_22
THEORY
2014
Paper 2, Variant 2
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Vaccination can protect against the infectious disease tuberculosis (TB). Define the terms: vaccination infectious disease. TB is an important disease worldwide. Table 2.1 shows recent information about TB cases reported during one year in six different countries. Table 2.1 country region number of cases number of cases per 100 000 population Germany Europe India Asia 2 300 000 Japan Asia 27 000 South Africa Africa 490 000 Swaziland Africa 15 000 United Kingdom Europe With reference to Table 2.1, explain the advantage of calculating the number of cases of TB per 100 000 population rather than stating the number of cases alone. Describe how a person may become infected with TB. Suggest why TB is more likely to be fatal in people who have HIV/AIDS than in those who do not have HIV/AIDS.
9700_s14_qp_23
THEORY
2014
Paper 2, Variant 3
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Questions Discovered
208