DP Biology (first assessment 2025)

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Question 19N.2.SL.TZ0.f.ii

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Date November 2019 Marks available [Maximum mark: 3] Reference code 19N.2.SL.TZ0.f.ii
Level SL Paper 2 Time zone TZ0
Command term Suggest Question number f.ii Adapted from N/A
f.ii.
[Maximum mark: 3]
19N.2.SL.TZ0.f.ii

Suggest possible reasons for the observed pattern of presence of antibodies in vaccinated mice.

[3]

Markscheme

a. low antibody level initially as mice not previously exposed to antigen/bacteria ✔

b. vaccination causes antibody production/development of immunity ✔

c. increased proportion of mice have been vaccinated in each successive month ✔

d. second vaccination/booster shot increases antibody level/speeds up antibody production ✔

e. memory cells produced so greater/faster antibody production ✔

f. many/rising numbers of nymphs which may spread the bacteria/antigens to mice ✔

Ignore any references to non-vaccinated/control mice – this means that no marks are awarded for them because the question is about vaccinated mice, but there is no penalty for including this information in an answer.

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