Antibodies are proteins made by lymphocytes. Antitoxins are antibodies that neutralise toxins released by some bacteria.
Diphtheria is a transmissible disease caused by a bacterium that releases a toxin capable of causing serious harm to the body.
A person is thought to have caught diphtheria. At a clinic, she is given an injection of antitoxin antibodies that protect against the diphtheria toxin. She is also given an injection of the diphtheria vaccine.
A few weeks later, she is given a second diphtheria vaccine injection.
Fig. 6.1 shows how the concentrations of the antitoxin antibodies and the antibodies produced in response to the vaccine change.
(a(i))[2]
Explain the benefit of giving the person an injection of antitoxin antibodies.
(a(ii))[3]
Explain how the two injections of the vaccine lead to better protection against diphtheria than the injection of antitoxin antibodies.
(b)[4]
Explain how antibodies protect the body from pathogens.
(c)[2]
State two functions of the lymphatic system apart from defence against disease.
Worked solution & mark scheme
This 11-mark question has a full step-by-step worked solution and mark scheme. One marking point: “passively acquired immunity” …