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Pearson Edexcel IAL Biology 6.8 Non-specific responses to infection

Practise explaining non-specific defences using macrophages, inflammation, lysozyme action and interferons in infection contexts.

Syllabus
First assessment 2019
Course
Biology YBI11
Level
A2

Exam points

  • describe phagocytosis of bacteria by macrophages, including engulfing and lysosomal digestion
  • explain how heat, swelling and pain link to inflammation and faster destruction of pathogens
  • explain interferon release by infected cells and its effect on viral replication in neighbours

6.8—Non-specific responses to infection question 1

[Maximum number: 6]

Rheumatoid arthritis is an inflammatory condition caused by the overactivity of the immune system.

Question (a)

(a)

The photographs show the hand of a person with rheumatoid arthritis and the hand of a person without rheumatoid arthritis.

Figure for Question (a) — Edexcel A-Level Biology A2

Hand with rheumatoid arthritis
Magnification ×0.2\times 0.2

Figure for Question (a) — Edexcel A-Level Biology A2

Hand without rheumatoid arthritis
Magnification ×0.2\times 0.2

[ 2 ]

Question (i)

(i)

Give one piece of evidence, shown in the photographs, that rheumatoid arthritis is an inflammatory condition.

[ 1 ]

Question (ii)

(ii)

Give two other signs of inflammation that are experienced in the hand of a person with rheumatoid arthritis.

[ 1 ]

Question (b)

(b)

Tumour necrosis factor (TNF) is a protein that can be released by several types of cell. It plays an important part in the immune response.

This protein binds to specific receptors on the surface of cell membranes stimulating chemical reactions inside the cell. As a result, a number of responses may occur that include inflammation and the stimulation of phagocytosis by macrophages.

Antibodies to TNF are used to treat rheumatoid arthritis.
Scientists have used a virus that infects bacteria to produce antibodies to human TNF.

The diagram summarises this process.

Figure for Question (b) — Edexcel A-Level Biology A2
[ 4 ]

Question (i)

(i)

Patients being treated with antibodies to TNF are more susceptible to tuberculosis (TB), which can be fatal.

Explain why patients being treated with antibodies to TNF can die from TB.

[ 4 ]
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