Biology 9700 · AS & A Level · Antibodies and vaccination

Antibodies and vaccination — practice question

Cholera is an infectious disease that is caused by the bacterial pathogen Vibrio cholerae. V. cholerae secretes a toxin called choleragen. Choleragen is a protein molecule composed of six polypeptides (subunits).
(a)[2]

Describe how V. cholerae passes from an infected person to an uninfected person.

(b)[3]

Fig. 3.1 shows a ribbon diagram of a choleragen molecule. Describe what the part of the molecule labelled T shows.

(c(i))[2]

Phagocytes have an important role in the immune response to a vaccine. Phagocytes contain many lysosomes. Describe the function of lysosomes in phagocytes.

(c(ii))[2]

Suggest the advantage of a vaccine that contains dead cells of V. cholerae and part of the choleragen molecule.

(d)[4]

The World Health Organization says that most cholera cases can be treated with oral rehydration therapy. To lower the chance of antibiotic resistance developing, antibiotics are recommended only for the most serious cases. Discuss the consequences of the development of antibiotic resistance in V. cholerae.

Worked solution & mark scheme

This 13-mark question has a full step-by-step worked solution and mark scheme. One marking point: Faeces from an infected person contaminate water or food

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