How does the concentration of chloride ions affect the binding of oxygen to hemoglobin?

A Chloride ions increase oxygen affinity
B Chloride ions decrease oxygen affinity ✓
C Chloride ions have no effect on oxygen binding
D Chloride ions compete with oxygen for binding sites

Explanation

Chloride ions can bind to hemoglobin, reducing its affinity for oxygen. This effect is more pronounced at lower pH levels, contributing to the Bohr effect where a decrease in pH (increase in acidity) results in a decrease in hemoglobin's oxygen affinity.

Source

Biochemistry textbooks by Stryer or Berg et al.
Hematology Hematology: Hemoglobin and Oxygen Transport Hematology: Hemoglobin and Oxygen Transport Hard MEDICAL Confidence: medium