Lesson 1.2.2

1.2.2 Blood clotting and its role in CVD Quiz: Pearson Edexcel Biology A (Salters-Nuffield), Unit 1

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

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Lesson 1.2.2, Blood clotting and its role in CVD: 20 multiple choice questions for the Pearson Edexcel Biology A (Salters-Nuffield) (9BI0), Unit 1: Lifestyle, Health and Risk, written with Revision Ninja.

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The 20 questions

  1. What is the role of thromboplastin in blood clotting?

    • It dissolves fibrin once the wound has healed to remove the clot
    • It catalyses the conversion of prothrombin into thrombin
    • It converts fibrinogen directly into fibrin without any other enzyme
    • It binds red blood cells together to form the clot's mesh

  2. Which enzyme converts fibrinogen into fibrin?

    • Thromboplastin
    • Thrombin
    • Prothrombin
    • Plasmin

  3. Which of these is the correct sequence in the blood-clotting process?

    • Fibrin is released, which converts thrombin to thromboplastin, which then converts prothrombin
    • Prothrombin is converted to fibrinogen, which then releases thromboplastin that makes thrombin
    • Thrombin is released from platelets, which converts fibrin to fibrinogen to form the clot
    • Thromboplastin is released, prothrombin is converted to thrombin, and thrombin converts fibrinogen to fibrin

  4. Why is a platelet plug formed at the site of injury before fibrin is made?

    • Platelets are needed to make prothrombin, which is essential before any clot can be formed
    • Platelets adhere to exposed collagen and aggregate, providing a rapid initial seal of the damaged vessel
    • Platelets are converted into fibrin, which then seals the wall of the artery at the damaged area
    • Platelets release thrombin, which then dissolves the endothelium so that repair can begin

  5. What is the function of the fibrin mesh in a blood clot?

    • It dissolves the endothelium to allow new cells to grow into the damaged area
    • It prevents platelets from sticking to the damaged wall so the bleeding can stop
    • It carries oxygen from the lungs to the damaged tissue during the repair process
    • It traps red blood cells and platelets to form a stable clot that seals the damaged wall

  6. Why does a clot that forms inside an atherosclerotic coronary artery pose a serious risk?

    • It makes the blood more viscous, which allows the heart to pump blood at lower pressure
    • It causes the heart to beat faster by stimulating the sinoatrial node directly
    • It immediately stops all blood flow to the lungs by blocking the pulmonary artery
    • It can block the lumen of the artery, cutting off oxygen supply to heart muscle

  7. Which drug class is used to reduce the risk of clot formation in cardiovascular disease?

    • Antihypertensives, which increase the clotting ability of platelets in the artery
    • Diuretics, which increase the concentration of thrombin in the plasma
    • Anticoagulants and platelet inhibitors, such as aspirin
    • Statins, which increase the rate at which fibrin is produced in the blood

  8. Which statement describes the role of calcium ions in blood clotting?

    • Calcium ions are removed from the clot by platelets so that fibrin can be formed
    • Calcium ions are the enzyme that converts fibrinogen into fibrin at the wound site
    • Calcium ions are required as cofactors for several steps in the clotting cascade
    • Calcium ions prevent thrombin from acting so that clotting is kept under control

  9. A patient takes an anticoagulant drug that inhibits the activity of thrombin. What is the most likely effect on the blood-clotting process?

    • Conversion of fibrinogen to fibrin is slowed, so clot formation is less likely
    • Thromboplastin is produced in greater amounts, which increases the rate of fibrin formation
    • Platelets adhere more strongly to collagen, which makes clots form faster
    • Conversion of fibrinogen to fibrin is speeded up, so clots form more quickly than normal

  10. Why does damage to the endothelium promote blood clotting?

    • Damaged endothelium releases haemoglobin, which directly converts fibrinogen to fibrin
    • The endothelium contains prothrombin, which becomes thrombin only when the wall is damaged
    • Exposed collagen and tissue factors activate platelets and the clotting cascade
    • The endothelium produces anticoagulants that are then lost, which allows red blood cells to stick

  11. Which of these best describes a thrombus?

    • A fragment of a red blood cell that is carried in the plasma to the liver for destruction
    • A blood clot that forms inside a blood vessel and may obstruct blood flow
    • A deposit of cholesterol in the wall of an artery that narrows the lumen over many years
    • A type of white blood cell that engulfs lipid in the endothelium and becomes a foam cell

  12. In a clotting experiment, the time for a sample of blood to clot is measured with and without a drug that blocks thromboplastin. What is the most likely result?

    • Clotting takes longer in the presence of the drug, because prothrombin conversion is delayed
    • Clotting takes less time in the presence of the drug, because thromboplastin is a clotting inhibitor
    • Clotting is unaffected, because thromboplastin is only needed after the fibrin mesh has formed
    • Clotting is faster only if the drug also blocks red blood cells from entering the clot

  13. Why are people with haemophilia at higher risk of bleeding?

    • They have too much fibrin in the plasma, which causes the blood to clot too quickly and fill vessels
    • They have a thicker endothelium that cannot be repaired after damage, which stops healing
    • They have excess platelets which block the lumen and so prevent the blood from leaving the wound
    • They lack or have defective clotting factors, so thrombin and fibrin formation is impaired

  14. Which statement is correct about the relationship between clotting and cardiovascular disease?

    • Clotting makes the arteries wider, which lowers blood pressure and reduces the risk of heart disease
    • Clots forming on a ruptured atherosclerotic plaque can block arteries and cause heart attacks or strokes
    • Clotting prevents atherosclerosis by removing lipid from the artery wall before it can build up
    • Clotting only occurs in veins, so it has no direct link to disease in coronary arteries

  15. Which substance is the substrate for thrombin in the clotting cascade?

    • Fibrinogen, which is converted into insoluble fibrin strands
    • Prothrombin, which is converted into fibrinogen as the clot forms
    • Collagen, which is converted into fibrin when the endothelium is damaged
    • Thromboplastin, which is converted into thrombin in the presence of calcium

  16. Which of these is a benefit of platelet inhibitors in cardiovascular disease?

    • They lower blood pressure, so that the clotting cascade starts more slowly in the arteries
    • They dissolve cholesterol in the artery wall, so plaques are removed and clots cannot form
    • They raise the platelet count, so that more platelets are available to seal wounds rapidly
    • They reduce platelet aggregation, which lowers the risk of a clot forming on a plaque

  17. What is the main risk of taking anticoagulant drugs?

    • Increased bleeding, because the blood takes longer to clot and wounds are slower to seal
    • Increased blood pressure, because anticoagulants constrict the arterioles in the body
    • Increased risk of atherosclerosis, because anticoagulants damage the endothelium directly
    • Increased cholesterol, because anticoagulants stop the liver from clearing LDL from the blood

  18. A student adds a calcium chelator to a blood sample to bind free calcium ions. What is the predicted effect on clotting?

    • Clotting is accelerated, because calcium ions inhibit thrombin and so their removal releases it
    • Clotting is inhibited, because calcium ions are needed as cofactors in the clotting cascade
    • Clotting is faster, because the removal of calcium ions increases the concentration of fibrin
    • Clotting is unaffected, because calcium ions are only needed for the contraction of muscle

  19. Which of these is a key difference between thrombin and fibrin?

    • Thrombin and fibrin are both enzymes that act on platelets to form a clot
    • Thrombin is found in red blood cells and fibrin is found in the endothelium
    • Thrombin is an enzyme, whereas fibrin is a fibrous protein that forms the clot network
    • Thrombin is a fibrous protein, whereas fibrin is an enzyme that converts prothrombin

  20. Why is prothrombin described as an inactive precursor?

    • It must be converted into thrombin before it can act on fibrinogen in the clotting cascade
    • It is destroyed by fibrin once the clot has formed, so it cannot be reused in the cascade
    • It is a hormone released by the liver that stops thrombin from being produced in the plasma
    • It is a lipid that binds platelets to the endothelium and prevents clotting from starting

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