Q10 - Altitude Adaptation in Deer Mouse Hemoglobin

Theoretical B Real exam question - full text reproduced under IBO's CC BY-NC-SA 4.0 license

Deer mice have a wide geographic range, e.g. with respect to altitude. This is partly explained by their respiratory physiology (Fig.).

A, oxygen saturation (%) of blood of deer mice from low and high altitude habitats as a function of the partial pressure of atmospheric oxygen PO₂; B, P50 is the partial PO₂ at which the blood is 50% O2-saturated, here plotted against the BPG (2,3-bisphosphoglycerate) : hemoglobin ratio. BPG affects the oxygen affinity of hemoglobin (from Tufts et al. 2013).

Figure 1. Figure 1.

Using the information and data, determine which of the statements are true or which are false.

A. Hemoglobin in high-altitude deer mice does not release oxygen as easily as compared to that low-altitude mice

B. High-altitude mice have lower P₅₀ than low-altitude mice

C. If BPG concentration in blood increases, the saturation curve in Fig. A will shift to the right

D. Assuming that adaptation to altitude is genetically determined, P₅₀ values will most likely remain the same if a mouse is transferred to another altitude

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Question reproduced from IBO 2015, Theoretical Exam B, licensed under CC BY-NC-SA 4.0 - attributed to the International Biology Olympiad. Open the full exam PDF · Community solutions (unofficial)