1. 1
   A student examined a stained blood smear under a microscope. Most of the cells visible were small, biconcave, disc-shaped cells with no nucleus, but a few larger cells with a distinct lobed nucleus were also present in much smaller numbers.

   (a)

   A student examined a blood smear under a microscope and identified small, biconcave, disc-shaped cells with no nucleus, present in very large numbers. Which blood component did the student identify?

   [1 mark]

   • ARed blood cells
   • BWhite blood cells
   • CPlatelets
   • DPlasma

   (b)

   What is the main function of the small, biconcave, disc-shaped cells identified by the student?

   [1 mark]

   • ATransporting hormones and nutrients in solution
   • BProducing antibodies against pathogens
   • CClotting blood at a wound
   • DTransporting oxygen around the body

   (c)

   Explain how the biconcave shape and absence of a nucleus in these cells help them to carry out their function efficiently.

   [2 marks]

   Total for question 1: 4 marks

2. 2
   A doctor examined a patient's blood test results during a bacterial infection and noted a raised number of the larger white blood cells with a lobed nucleus, as well as normal platelet and red blood cell counts.

   (a)

   A doctor examined a patient's blood test results and noted a raised number of the larger cells with a lobed nucleus, along with signs of a bacterial infection. Which cells were most likely raised in number?

   [1 mark]

   • APlatelets
   • BRed blood cells
   • CWhite blood cells (phagocytes)
   • DPlasma proteins only

   (b)

   How do these white blood cells help defend the patient's body against the bacterial infection?

   [1 mark]

   • ABy transporting oxygen to the site of infection
   • BBy engulfing and digesting the bacteria (phagocytosis)
   • CBy forming a clot to seal the infected area
   • DBy transporting carbon dioxide away from the infection site

   (c)

   Explain the difference between the roles of phagocytes and lymphocytes, another type of white blood cell, in defending the body against pathogens.

   [2 marks]

   Total for question 2: 4 marks

3. 3
   A patient with a deep cut on their arm showed normal, effective blood clotting at the wound site, which stopped the bleeding within a few minutes. Doctors also noted the wound showed no signs of infection a few days later.

   (a)

   A patient with a deep cut showed normal, effective blood clotting at the wound site, which stopped the bleeding within a few minutes. Explain the roles of platelets and plasma proteins in forming this blood clot.

   [3 marks]

   (b)

   Discuss the importance of blood clotting in preventing both blood loss and infection, and explain how the components of plasma contribute to the transport functions of blood more generally.

   [4 marks]

   Total for question 3: 7 marks

4. 4
   A haematologist analysed a full blood count from a healthy volunteer, examining the relative proportions and structural features of red blood cells, white blood cells, platelets and plasma, and explaining the role each component plays in maintaining health.

   (a)

   Describe the structure and functions of the four main components of blood: red blood cells, white blood cells, platelets and plasma, explaining how each component's structure suits it to its particular role.

   [6 marks]

   (b)

   The haematologist then examined a blood sample from a patient with a bone marrow disorder that reduced production of all blood cell types, while plasma composition remained largely normal. Discuss the likely health consequences of reduced numbers of red blood cells, white blood cells and platelets, explaining how each deficiency would affect the patient differently.

   [6 marks]

   Total for question 4: 12 marks

End of questions