Biology 9700 · AS & A Level · Antibodies and vaccination

Antibodies and vaccination — practice question

The vaccine used to control tuberculosis (TB) is called Bacillus Calmette-Guérin (BCG). It contains live bacteria that have been chosen so that they do not cause illness in humans. Fig. 5.1 shows a macrophage as it engulfs the bacteria in the vaccine.
(a(i))[1]

Name the pathogen responsible for TB.

(a(ii))[2]

Describe how this pathogen is passed from one host to another.

(b)[5]

Describe the sequence of events in the body from the moment the macrophage has engulfed the bacteria until antibodies are produced in response to the BCG vaccine.

(c)[3]

Vaccines, such as BCG, stimulate the production of memory cells. Explain the role of memory cells in the body’s defence against the TB pathogen.

(d)[3]

Suggest why vaccination with BCG has not yet eliminated TB.

Worked solution & mark scheme

This 14-mark question has a full step-by-step worked solution and mark scheme. One marking point: “$\textit{Mycobacterium tuberculosis}$ or $\textit{Mycobacterium bovis}$” …

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