IB Biology SL 3.2.3 Blood clotting Question Bank
Practise IB Biology SL 3.2.3 by explaining how platelets and fibrin seal damaged blood vessels.
- Syllabus
- First assessment 2025
- Course
- Biology SL
- Level
- SL
Exam points
- Explain how platelets and clotting factors form a blood clot.
- Relate fibrin formation to protection from blood loss and infection.
C3.2.3—Blood clotting question 1
[Maximum number: 7]
People with the inherited disease hemophilia have a deficiency in one of the proteins that act as clotting factors in blood.
Explain how blood clotting occurs and the consequence for a person who has hemophilia.
Clotting process:
Blood clotting seals cuts in the skin.
Clotting factors are released from platelets.
Thrombin is activated.
A cascade reaction occurs with thrombin.
Thrombin causes fibrinogen to be converted to fibrin.
Fibrin forms a clot/blocks the cut/prevents blood from being lost.
Consequences of hemophilia:
If a person does not have enough clotting factors/has hemophilia, the clot will not form.
Pathogens can enter the body more easily.
Blood will be lost from a cut, affecting blood pressure / causing bleeding to death.
Loss of blood affects the amount of hemoglobin/O2 carried around the body.
Reference to lifestyle / menstrual/birth problems, e.g. surgery or contact sports.
[7 max]
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