Download TB: biology homework revision question

5. Tuberculosus
1.
(a)
Describe how tuberculosis (TB) is caused
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(Total 3 marks)
2.
(a)
Explain what is meant by the term infection.
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(b)
Tuberculosis is a disease caused by the bacterium Mycobacterium tuberculosis. The
disease is caught when secretions from the lungs and airways of an infected person are
inhaled and the bacteria pass down to the lungs. Tuberculosis is characterised by
persistent coughing with blood-stained mucus.
Tuberculosis can be treated with antibiotics. Patients need to be given three or four
different antibiotics (combination therapy) for several months. It is important that the
drugs are taken every single day and that the medication continues to be taken even after
the patient feels better, to prevent the development of antibiotic resistance.
(i)
With reference to the effect of M. tuberculosis on lung tissue, suggest how the
bacteria cause the coughing of blood-stained mucus.
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(ii)
Explain how antibiotic resistance develops.
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(2) (Total 6 marks)
A2 Unit 4: The Natural Environment and Species Survival: Topic 6: Infection, immunity and forensics
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5. Tuberculosus
3.
The diagram below shows the possibility of developing tuberculosis (TB) when people are
exposed to the bacterium Mycobacterium tuberculosis.
(a)
Name the organ which is the most commonly infected by M. tuberculosis.
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(1)
(b)
Suggest why 90% of people who are infected by M. tuberculosis never develop TB.
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A2 Unit 4: The Natural Environment and Species Survival: Topic 6: Infection, immunity and forensics
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5. Tuberculosus
(c)
Outline the treatment for those people with active TB.
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(3) (Total 6 marks)
4.
Tuberculosis (TB) is caused by the bacterium, Mycobacterium tuberculosis.
(a)
The table below lists five structural features that may be found in bacteria and viruses.
Put a cross in the box if the structural feature is present.
Structural feature
Bacteria
Viruses
Mesosome
Capsid
Nucleic acid
Cytoplasm
Ribosome
(5)
(b)
The table below shows the number of new TB cases recorded in 1994 and in 2004 from
four different geographical regions. These data exclude people who are HIV positive.
Year
(i)
Number of new TB cases per 100 000 of the population
Africa
Asia
South America
Europe
1994
148
629
98
48
2004
281
535
59
104
Describe the trends shown by the data.
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A2 Unit 4: The Natural Environment and Species Survival: Topic 6: Infection, immunity and forensics
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5. Tuberculosus
(ii)
HIV positive people were excluded from the data. If they had been included
suggest how the data would differ. Give an explanation for your answer.
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(c)
TB is increasing in some countries which have well-funded health services. Suggest two
reasons for this.
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(Total 12 marks)
A2 Unit 4: The Natural Environment and Species Survival: Topic 6: Infection, immunity and forensics
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5. Tuberculosus
5.
Many people infected with the bacterium that causes tuberculosis (TB) do not develop the
disease for a number of years.
(a)
Suggest how some TB bacteria avoid being destroyed by the immune system for a
number of years.
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(b)
Describe the role of B-cells and T-cells in preventing the development of the symptoms
of TB in an infected person.
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(c)
(i)
Suggest why a patient infected with TB is more likely to develop symptoms of the
disease if they are also infected by HIV.
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(ii)
Give two symptoms which are likely to occur in a person with TB.
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(Total 8 marks)
A2 Unit 4: The Natural Environment and Species Survival: Topic 6: Infection, immunity and forensics
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