What is the Difference Between Bohr Effect and Root Effect?

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The Bohr Effect and Root Effect are both physiological phenomena related to the interaction between hemoglobin and oxygen. However, they differ in the way they affect the oxygen-carrying capacity of hemoglobin:

  • Bohr Effect: This occurs in most vertebrates and is a change in proton concentration that induces a modification of the hemoglobin-oxygen affinity. The main feature of the Bohr effect is the shift in the oxygen dissociation curve caused by changes in the concentration of hydrogen ions (protons) in the blood. An increase in carbon dioxide can result in a decrease in blood pH, making hemoglobin proteins release their load of oxygen. Conversely, a decrease in carbon dioxide can provoke an increase in pH that can result in hemoglobin picking up more oxygen.
  • Root Effect: This phenomenon is predominantly observed in fish hemoglobin and is characterized by an increase in proton or carbon dioxide concentration (lower pH) that lowers the hemoglobin-oxygen affinity and carrying capacity for oxygen. The Root effect is distinguished from the Bohr effect in that it not only reduces the affinity to oxygen but also decreases the carrying capacity for oxygen. Hemoglobins showing the Root effect show a loss of cooperativity at low pH, resulting in the Hb-O2 dissociation curve being shifted downward and not just to the right. At low pH, hemoglobins exhibiting the Root effect do not become fully oxygenated even at oxygen tensions up to atmospheric levels.

In summary, the key difference between the Bohr effect and the Root effect is that the former only reduces the affinity to oxygen, whereas the latter reduces both the affinity and carrying capacity for oxygen.

Comparative Table: Bohr Effect vs Root Effect

The Bohr Effect and Root Effect are both phenomena related to the hemoglobin-oxygen combinations, but they have distinct differences. Here is a table comparing the two:

Feature Bohr Effect Root Effect
Definition The Bohr Effect is the shift in the oxygen dissociation curve caused by changes in the concentration of hydrogen ions (protons) in the blood. The Root Effect indicates that an increased proton or carbon dioxide concentration lowers the hemoglobin's affinity and carrying capacity for oxygen.
Affinity In the Bohr Effect, only the affinity to oxygen is reduced. In the Root Effect, both affinity and carrying capacity for oxygen are reduced.
Discoverer The Bohr Effect was first described by the Danish physiologist Christian Bohr in 1904. The Root Effect was discovered later, and its molecular mechanisms were elucidated by E. Spiess and R. Scholander in 1954.
pH Change An increase in carbon dioxide can result in a decrease in blood pH, which in turn makes hemoglobin proteins release their load of oxygen. A decrease in carbon dioxide can provoke an increase in pH that can result in hemoglobin picking up more oxygen. The Root Effect results in incomplete Hb-O2 saturation at low pH, despite atmospheric PO2 levels.
Species The Bohr Effect is observed in humans and other mammals. The Root Effect is observed in fish and some invertebrates.

In summary, the Bohr Effect is a shift in the oxygen dissociation curve caused by changes in the concentration of hydrogen ions in the blood, while the Root Effect indicates that an increased proton or carbon dioxide concentration lowers the hemoglobin's affinity and carrying capacity for oxygen. The Bohr Effect is observed in humans and other mammals, whereas the Root Effect is observed in fish and some invertebrates.