Which condition during exercise induces the Bohr effect in hemoglobin?

• A. Decreased body temperature
• B. Decreased concentration of lactic acid
• C. Increased blood pH (alkalosis)
• D. Increased concentration of carbon dioxide (\(\mathrm{CO_2}\)) in the blood

Answer: (D)

Verified step by step guidance

1. Understand the Bohr effect: The Bohr effect describes how hemoglobin's oxygen-binding affinity decreases in response to certain conditions, facilitating oxygen release to tissues. These conditions include increased carbon dioxide (\(\mathrm{CO_2}\)) concentration, decreased pH (acidosis), and increased temperature.
2. Recognize the physiological changes during exercise: During exercise, muscle cells produce more carbon dioxide (\(\mathrm{CO_2}\)) as a byproduct of increased cellular respiration. Additionally, lactic acid production lowers blood pH, creating an acidic environment.
3. Relate increased \(\mathrm{CO_2}\) concentration to the Bohr effect: Higher \(\mathrm{CO_2}\) levels in the blood lead to the formation of carbonic acid (\(\mathrm{H_2CO_3}\)), which dissociates into hydrogen ions (\(\mathrm{H^+}\)) and bicarbonate ions (\(\mathrm{HCO_3^-}\)). The increase in \(\mathrm{H^+}\) ions lowers blood pH, enhancing the Bohr effect.
4. Eliminate incorrect options: Decreased body temperature and decreased lactic acid concentration do not occur during exercise and would not induce the Bohr effect. Increased blood pH (alkalosis) would actually reduce the Bohr effect, as it increases hemoglobin's oxygen-binding affinity.
5. Conclude the correct condition: The increased concentration of carbon dioxide (\(\mathrm{CO_2}\)) during exercise is the primary factor inducing the Bohr effect, facilitating oxygen release to active tissues.