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Question 343
Physiology → Haematology
Classification
Question
SSBAQuestion Header
Glucose uptake by mature human erythrocytes is being considered in relation to their cellular structure.
Question Stem
Which feature best explains why erythrocyte glucose uptake is not controlled by insulin?
Options
A
Absence of Golgi apparatus
B
Absence of mitochondria
C
Absence of a nucleus
D
Dependence on glycolysis for energy
E
Absence of an insulin receptor
Explanation
Mature human erythrocytes do not have insulin receptors; consequently, their glucose uptake is not controlled by insulin. They also lack nuclei, mitochondria and Golgi apparatus, and obtain energy through glycolysis, but these features do not provide the stated explanation for insulin-independent glucose uptake.
Option Validity
A) Absence of Golgi apparatus is a feature of mature erythrocytes but does not explain the lack of insulin control of glucose uptake.
B) Absence of mitochondria means erythrocytes derive energy through glycolysis; it is not the reason glucose uptake is insulin-independent.
C) Mature erythrocytes are non-nucleated, but absence of the nucleus is not the specific mechanism determining insulin-independent glucose uptake.
D) Glycolysis supplies erythrocyte energy because mitochondria are absent, but this does not itself explain the lack of insulin control.
Further Reading
Saxena. Textbook for MRCOG-1. Physiology - Haematology - Red Blood Cells, p.67.