IB Biology HL 3.2.3 Blood clotting Question Bank
Practise IB Biology HL 3.2.3 by analysing the enzyme cascade and experimental evidence in blood clotting.
- Syllabus
- First assessment 2025
- Course
- Biology HL
- Level
- HL
Exam points
- Analyse the sequence from platelet activation to fibrin formation in a clotting cascade.
- Evaluate the roles of thrombin, platelets and anticoagulants in clot formation.
C3.2.3—Blood clotting question 1
Plasma proteins, sCD 62 P and sCD 40 L , are involved in the activation of blood platelets. The von Willebrand factor causes the platelets to stick to blood vessel walls. Fibrinogen is a marker for inflammation of the blood system. All four are biological markers that indicate a risk of thrombosis.
During the 2008 Olympic games held in Beijing, the Chinese authorities temporarily reduced air pollution levels by restricting emissions from motor vehicles and industry. Doctors used this event to test the effects of air pollution on these biological markers. The graph shows the mean percentage changes in the levels of biological markers in volunteers during the study.
Thromboses, including coronary thrombosis, could be a consequence of a build-up of these biomarkers.
State the role of platelets in thromboses.
All question bank results loaded