Answer:
Step-by-step explanation:
Oxygen has low solubility in water, so very little O₂ can be delivered to tissues by simply being dissolved in blood plasma. Animals use carrier proteins to transport O₂. Red blood cells contain hemoglobin, which is the carrier protein used by vertebrates.
In contrast, most carbon dioxide produced by tissues is transported in the blood to the lungs as HCO₃⁻(bicarbonate ions).
The equilibrium equation for carbon dioxide in the blood is:
CO₂+ H₂O ↔ H₂CO₃ ↔ H⁺ + HCO₃⁻
Carbonic acid
The conversion to bicarbonate ions keeps the partial pressure of CO₂ in the blood plasma low, facilitating diffusion away from the tissues.
The pH of the blood affects the process. As you can see in the equilibrium equation for CO₂, an increase of this gas results in a decrease of pH because of the formation of carbonic acid. The acidic pH decreases hemoglobin's affinity for oxygen, thus stimulating the release of O₂ to the tissues (that are producing a lot of CO₂ and need oxygen).This is known as the Bohr effect.