What is the role of carbon dioxide in the regulation of hemoglobin's oxygen-binding affinity?

A It increases the affinity of hemoglobin for oxygen
B It has no effect on the oxygen-binding affinity of hemoglobin
C It decreases the affinity of hemoglobin for oxygen ✓
D It irreversibly binds to hemoglobin, reducing its ability to transport oxygen

Explanation

Carbon dioxide binds to hemoglobin, forming carbaminohemoglobin, which reduces the affinity of hemoglobin for oxygen, facilitating the release of oxygen to tissues.

Mnemonic

CO2 = 'come out 2', as in come out of hemoglobin

Source

Guyton and Hall Textbook of Medical Physiology
Hematology Hematology: Hemoglobin and Oxygen Transport Hematology: Hemoglobin and Oxygen Transport Medium MEDICAL Confidence: high