A
B
C
D
E
100
1. The diagram shows a wound with the damaged blood vessel. X cells clumps at the damaged site and releases chemical substances. What are X cells?
A. Platelets
B. Erythrocytes
C. Agranulocytes
D. Granulocytes
A. Platelets
100
2. Blood clotting mechanism is important as the following reasons EXCEPT
A. Prevent excessive blood loss when there is a damage of the blood vessel
B. Prevent the entry of microorganisms and pathogens into the body through the wound
C. Maintain a low blood pressure
D. Maintain the circulation of blood in a closed circulatory system
C. Maintain a low blood pressure
100
3. Which of the following blood cells play an important role in the blood clotting mechanism?
A. Thrombocytes
B. Erythrocytes
C. Leucocytes
A. Thrombocytes
100
4. Platelets group together and release a complex enzyme X. What is X?
A. Prothrombin
B. Thrombin
C. Fibrinogen
D. Thrombokinase
D. Thrombokinase
100
5. A blood clot moving in the bloodstream is called an embolus.
A. True
B. False
A. True
200
6. The following three substances are required to convert prothrombin into thrombin EXCEPT for
A. Thrombokinase
B. Fibrinogen
C. Calcium ions
D. Vitamin K
B. Fibrinogen
200
7. Thrombokinase changes ______ to ______.
A. fibrin ... fibrinogen
B. thrombin ... prothrombin
C. fibrinogen ... fibrin
D. prothrombin ... thrombin
D. prothrombin ... thrombin
200
8. Thrombin is a type of active plasma protein that catalyses the conversion of ______ to ______.
A. fibrin... fibrinogen
B. fibrinogen ... fibrin
C. prothrombin ... thrombin
D. thrombin ... prothrombin
B. fibrinogen ... fibrin
200
9. The inactive plasma protein involved in the blood clotting mechanism is known as ________.
A. Fibrin
B. Thrombin
C. Fibrinogen
D. Prothrombin
D. Prothrombin
200
10. Which of the following is the importance of blood clotting?
I. Prevent excessive blood loss
II. Prevent the entry of microorganisms
III. Prevent lowering of blood pressure
IV. Prevent the entry of oxygen into the blood
A. I, II, IV
B. I, III, IV
C. I, II, III
D. II, III, IV
C. I, II, III
300
11. Which reaction is catalysed by thromboplastin (thrombokinase)?
A. Conversion of prothrombin to thrombin
B. Conversion of prothrombin to fibrin
C. Conversion of thrombin to prothrombin
D. Conversion of fibrinogen to fibrin
A. Conversion of prothrombin to thrombin
300
12. Blockage in carotid arteries may lead to a heart attack while blockage in the coronary arteries may lead to stroke.
A. True
B. False
B. False
300
13. Thrombin, in turn, catalyses the conversion of the soluble protein fibrin to fibrinogen, which serves as a net that traps blood cells.
A. True
B. False
B. False
300
14. Haemophilia is a disease associated with blood clotting in which there is a clot formation inside an unbroken blood vessel.
A. True
B. False
B. False
300
15. What is the role of fibrin in blood clotting?
A. Acts as an enzyme
B. Forms a mesh of fibres to cover the wound
C. Causes smooth muscles in blood vessels to contract
D. Starts off the whole process
B. Forms a mesh of fibres to cover the wound
400
16. Ariana lack of clotting factors that cause her blood to unable to clot when she is having a cut.
Name this disease.
A. Haemophilia
B. Talasemia
C. Thrombosis
D. Embolism
A. Haemophilia
400
17. A boy accidentally cut his finger, the blood clots occur slowly. What caused the blood to clot slowly?
A. Lack of vitamin D in his meal
B. Lack of vitamin K in his meal
C. The blood of the boy is infected with pathogens
D. The blood of the boy flow with high pressure at the wound
B. Lack of vitamin K in his meal
400
18. A gardener experiences non-stop bleeding after hurting his foot while gardening.
What will happen if his blood is unable to clot?
A. Blood pressure decreases
B. Blood capillaries enlarge
C. The rate of heart heat increases
D. The rate of respiration increases
A. Blood pressure decreases
400
19. When blood coagulates on a vessel wall in the absence of a known injury, it is correctly referred to as:
A. embolus.
B. hemostasis.
C. thrombus.
D. sepsis
C. thrombus.
400
20. All of the following proteins are soluble, EXCEPT
A. fibrin
B. fibrinogen
C. thrombin
D. prothrombin
A. fibrin
500
21. A clot in the blood stream (commonly found in the legs) that breaks free and starts to travel can lodge in brain or lungs. This is called a/an:
A. thrombus
B. embolus
C. heparin
D. hematoma
B. embolus
500
22. What is the difference between thrombosis and embolism?
-Thrombosis occurs when a thrombus, or blood clot, develops locally in a blood vessel and reduces the flow of blood through the vessel.
-Embolism occurs when a piece of a blood clot, foreign object, or other bodily substance that moves in the bloodstream. It breaks off from where it is formed, travels to another area of your body, becomes stuck in a blood vessel and largely obstructs blood flow.
500
23. 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.
500
24. Explain why the formation of the 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.
500
25. 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.