Question 18M.3.HL.TZ2.21
| Date | May 2018 | Marks available | [Maximum mark: 9] | Reference code | 18M.3.HL.TZ2.21 |
| Level | HL | Paper | 3 | Time zone | TZ2 |
| Command term | Deduce, Outline, Suggest | Question number | 21 | Adapted from | N/A |
The hematocrit is the volume percentage fraction of erythrocytes in blood.
From the diagram, deduce the effect of the disease polycythemia on the proportion of erythrocytes in total blood volume.
[1]
the proportion/percentage increases «from 45 % to 70%»
Suggest how high altitude could lead to polycythemia.
[2]
a. more erythrocytes/hemoglobin produced to compensate
b. low oxygen «partial» pressure «at high altitude»
c. lower oxygen saturation «of hemoglobin at high altitude»
d. less oxygen carried to tissues/hypoxia
Suggest how changes in hemoglobin could help humans become better adapted to living at high altitude.
[3]
a. induced conformational change in the structure of the hemoglobin molecule occurs
b. «this» hemoglobin has higher affinity for oxygen
c. saturation curve shifted to the left «because of low O2 levels»
d. «this» hemoglobin becomes more saturated at lower partial pressures of oxygen
e. increased hematocrit/concentration of hemoglobin/red blood cells to carry more O2
Allow answers in an annotated diagram.
Outline the stages involved in the recycling of erythrocytes by the liver.
[3]
a. phagocytosis of erythrocytes by Kupffer cells
b. hemoglobin is split into globin and heme group
c. globin is re-used in protein synthesis
d. heme group broken down into iron and bilirubin
e. iron is carried back to the bone marrow «to produce new hemoglobin/erythrocytes»