Blood, clotting and atherosclerosisEdexcel A-Level Biology B: Subtopic test

1. 1
   A blood film from a patient with a bacterial infection shows a raised number of white blood cells. Many of these cells have a nucleus divided into several lobes and granules in the cytoplasm. The film also contains large numbers of red blood cells and small cell fragments.

   (a)

   Which type of white blood cell is most likely to be the cells described in the blood film?

   [1 mark]

   • ALymphocytes
   • BNeutrophils
   • CMonocytes
   • DPlatelets

   (b)

   Which statement about the red blood cells in the film is correct?

   [1 mark]

   • AThey contain a large nucleus that controls haemoglobin synthesis
   • BThey are spherical, which gives the smallest surface area for gas exchange
   • CThey contain granules that release clotting factors
   • DThey have no nucleus, leaving more room for haemoglobin

   (c)

   Explain how the neutrophils help to defend the patient against the bacterial infection.

   [2 marks]

   Total for question 1: 4 marks

2. 2
   A man has a rare inherited condition in which his liver cannot make prothrombin. His platelet count and the concentration of fibrinogen in his plasma are normal. When he cuts himself, the bleeding continues for much longer than normal.

   (a)

   Which substance is formed from prothrombin when a blood vessel is damaged?

   [1 mark]

   • AFibrin
   • BThromboplastin
   • CThrombin
   • DFibrinogen

   (b)

   Which event in the blood clotting sequence can still occur in this man after a cut?

   [1 mark]

   • APlatelets stick to the damaged vessel wall and form a plug
   • BProthrombin is converted into thrombin
   • CFibrinogen is converted into a mesh of insoluble fibrin
   • DA fibrin mesh traps red blood cells to form a stable clot

   (c)

   Explain why the man's bleeding continues for much longer than normal.

   [2 marks]

   Total for question 2: 4 marks

3. 3
   A 58-year-old man smokes 20 cigarettes a day, eats a diet high in saturated fat and has high blood pressure. A scan shows that one of his coronary arteries is partly blocked by an atheroma.

   (a)

   Describe how an atheroma develops in the wall of an artery.

   [3 marks]

   (b)

   Explain how the atheroma in the coronary artery could lead to angina and to a myocardial infarction (heart attack).

   [4 marks]

   Total for question 3: 7 marks

4. 4
   A doctor is explaining to a patient who has just been diagnosed with early atherosclerosis how blood normally clots when a blood vessel is damaged, and how his lifestyle affects the health of his arteries.

   (a)

   Describe the sequence of events that leads to the formation of a blood clot when a blood vessel is damaged.

   [6 marks]

   (b)

   The doctor advises the patient to stop smoking, to reduce the saturated fat in his diet and to take regular exercise. Explain how each piece of advice could reduce the risk of his atherosclerosis becoming worse.

   [6 marks]

   Total for question 4: 12 marks

End of questions