Which of the following promotes oxygen release from hemoglobin?
a. A decrease in temperature
b. An increase in O₂ level.
c. A decrease in pH
d. A decrease in carbonic anhydrase activity

Verified step by step guidance

1. Understand the Bohr effect: The Bohr effect describes how changes in pH and carbon dioxide concentration affect hemoglobin's affinity for oxygen. A decrease in pH (more acidic environment) or an increase in carbon dioxide concentration promotes oxygen release from hemoglobin.
2. Analyze the options: Consider how each option affects hemoglobin's ability to release oxygen. A decrease in temperature generally stabilizes hemoglobin's structure, making it less likely to release oxygen.
3. Consider the role of pH: A decrease in pH (option c) indicates an increase in hydrogen ion concentration, which can lead to a conformational change in hemoglobin, reducing its affinity for oxygen and promoting oxygen release.
4. Evaluate the effect of carbonic anhydrase: Carbonic anhydrase is an enzyme that catalyzes the conversion of carbon dioxide and water to bicarbonate and protons. A decrease in its activity (option d) would lead to less production of protons, potentially increasing pH and reducing oxygen release.
5. Conclude based on the Bohr effect: Given the options, a decrease in pH (option c) is most consistent with promoting oxygen release from hemoglobin due to the Bohr effect.

Key Concepts

Hemoglobin and Oxygen Binding

Hemoglobin is a protein in red blood cells responsible for transporting oxygen from the lungs to tissues. It binds oxygen in the lungs and releases it in tissues where oxygen levels are lower. The binding and release of oxygen are influenced by various factors, including temperature, pH, and the presence of other molecules like carbon dioxide.

Bohr Effect

The Bohr Effect describes how changes in pH and carbon dioxide concentration affect hemoglobin's affinity for oxygen. A decrease in pH (more acidic conditions) or an increase in carbon dioxide levels leads to hemoglobin releasing oxygen more readily. This is because hydrogen ions and carbon dioxide bind to hemoglobin, altering its structure and reducing its affinity for oxygen.

Carbonic Anhydrase Activity

Carbonic anhydrase is an enzyme that catalyzes the conversion of carbon dioxide and water into carbonic acid, which dissociates into bicarbonate and hydrogen ions. This reaction is crucial for maintaining acid-base balance in blood and facilitating carbon dioxide transport. A decrease in carbonic anhydrase activity would slow this conversion, potentially affecting pH and, consequently, hemoglobin's oxygen release.