Describe the composition of human blood.

Mark scheme

Marking points from the official mark scheme (Oct/Nov 2022). The mark or mark type is shown in brackets.

1. [1] plasma ;
2. [1] dissolved (named) food substances ;
3. [1] other plasma component, e.g. urea, carbon dioxide, hormones, antibodies, fibrinogen ;
4. [1] red blood cells ;
5. [1] white blood cells / lymphocytes / phagocytes ;
6. [1] platelets ;
7. [1] reference to relative percentage of cellular components and plasma with one of the figures quoted ;
8. [1] concentration of glucose ;
9. [1] detection of diabetes ;
10. [1] concentration of urea ;
11. [1] detection of kidney disease ;
12. [1] concentration / number of red blood cells ;
13. [1] ability to deliver oxygen to tissues / indication of shortage of iron in the diet / indication of anaemia ;
14. [1] shape of red blood cells ;
15. [1] indication of sickle cell anaemia ;
16. [1] concentration / number of white blood cells ;
17. [1] reference to cancer / leukaemia / infection / infectious disease, e.g. AIDS;
18. [1] concentration of cholesterol ;
19. [1] reference to occlusion of arteries / consequences of occlusion of arteries ;
20. [1] presence of specific antibodies ;
21. [1] detecting immunity / previous exposure to pathogen ;
22. [1] AVP ;;