Formative Practice 10.4 (Form 4 Biology Textbook Exercise and Answer)

Question 1:
At the end of the blood clotting mechanism, fibrin will be formed to trap erythrocytes. Explain the meaning of fibrin and its function.

Fibrin is the strand of protein fibre that prevents blood loss when a person is wounded, and entry of microorganisms such as bacteria and foreign substances into the blood.

Question 2:
Describe two health issues related to blood clotting.

Haemophilia and thrombosis

Question 3:
Explain the mechanism of blood clotting.

• Clumped platelets, damaged cells and clotting factor form thrombokinase

• Thrombokinase (in the presence of Ca2+ and vitamin K) converts prothrombin into thrombin

• Thrombin converts fibrinogen to fibrin

• Fibrin forms a mesh of fibres across the wound and prevents loss of blood.

Question 4:
Explain why the formation of blood clots in the blood vessel can cause a heart attack.

If blood clot is formed in the coronary artery, the cardiac muscles may die or suffer permanent damage due to the lack of oxygen supply. This may lead to a heart attack.

Leave a Comment