CAIE IGCSE Biology 9.4 Blood Questions

Practise blood questions on plasma, red cells, white cells and platelets, linking diagrams and tables to transport, defence and clotting functions.

Syllabus
2026–2028
Course
Biology 0610

Exam points

  • identify plasma, red blood cells and platelets from descriptions, diagrams or transport clues
  • link haemoglobin in red blood cells to oxygen binding and transport, including abnormal haemoglobin effects
  • describe platelet involvement, fibrinogen-to-fibrin conversion and mesh formation during clotting
  • state how a clot prevents blood loss and blocks pathogen entry through a wound

Question 1

[Maximum number: 1]

Tissue plasminogen activators (TPAs) are human proteins that are used as drugs to break down blood clots.

TPAs break down blood clots by activating plasminogen. Plasminogen is a protein that is always present in the blood.

When activated, plasminogen forms a protease that breaks down fibrin molecules.

Plasminogen is found in the plasma.

State what is meant by the term plasma.

Question 2

[Maximum number: 7]

Fig. 6.1 is a photomicrograph of a blood clot.

Fig. 6.1

Fig. 6.1

Question (a)

(a)

Describe how a blood clot forms.

Use the letters in Fig. 6.1 in your answer.

[ 5 ]

Question (b)

(b)

State the importance of blood clotting.

[ 2 ]

Question 3

[Maximum number: 4]

Some blood-clotting disorders can be inherited.

Describe the process of blood-clotting.

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