DP Biology (first assessment 2025)

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Question 19M.2.SL.TZ2.3b

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Date May 2019 Marks available [Maximum mark: 3] Reference code 19M.2.SL.TZ2.3b
Level SL Paper 2 Time zone TZ2
Command term Outline Question number b Adapted from N/A
b.
[Maximum mark: 3]
19M.2.SL.TZ2.3b
(b)

Outline the actions taken by the body to avoid infection when the skin is cut.

[3]

Markscheme

a. platelets/cut tissues release clotting factors ✔ Mp a requires student to identify source of clotting factors.

b. «clotting factors» activate thrombin «from prothrombin» ✔

c. thrombin converts fibrinogen to fibrin ✔

d. «fibrin» forms a clot/scab/mesh that seals the cut ✔

e. phagocytic white blood cells ingest pathogens ✔

Examiners report

This question about clotting was well answered with most being able to correctly identify the roles of clotting factors, fibrinogen and thrombin, though in a number of cases, specific details were lacking.

Syllabus sections