Question

What percentage of $CO_2$ is transported as $HbCO_2$?
A. 42 %
B. 10 %
C. 70 %
D. 50 %

Answer 1

Carbaminohemoglobin ($HbCO_2$) is a complex of haemoglobin and carbon dioxide and is among the mechanisms wherein carbon dioxide is present in the blood. The oxidation status of haemoglobin is essential in determining the amount of $CO_2$ that could be bound, with deoxygenated haemoglobin providing a stronger$CO_2$ affinity than$O_2$.

Complete answer: Carbaminohemoglobin is produced once carbon dioxide attaches to haemoglobin, dropping the affinity for oxygen to haemoglobin through Bohr impact. In the lack of oxygen, unbound haemoglobin molecules are much more inclined to become carbaminohaemoglobin. In capillary tissues, CO$_2$ binds with free haemoglobin-amino groups to produce carbaminohaemoglobin, in pulmonary vascular cells, this mechanism is inverted to release CO$_2$ into alveoli. This type of distribution is restricted to just approximately 10% of the carbon dioxide carried in the bloodstream. The effect of Haldane is associated with the increased affinity of deoxygenated haemoglobin for $H^+$, that leads to an increased affinity of haemoglobin for carbon dioxide and $H^+$ for the discharge of oxygen to the cells, whereby the body got to get rid of, which can then be delivered to the lungs for clearance.
So, the correct answer is (B).
Additional Information:
Haemoglobin will adhere to four carbon dioxide molecules. The carbon dioxide molecules comprise a carbamate of the four terminal-amine groups of the four protein chains throughout the deoxy form of the compound. Thereby, one haemoglobin molecule would transmit four carbon dioxide molecules back to the lungs, in which they are discharged once the molecule switches back in the form of oxyhemoglobin. For patients with respiratory disease, the lungs may not have been able to enhance alveolar airflow in the face of elevated amounts of CO$_2$ dissolved. These are partially caused by the fact that certain patients with emphysema could have a rise in PaCO$_2$ (partial arterial dissolved carbon dioxide pressure) after additional oxygen, even if the CO$_2$ content stays the very same.

Note: CO$_2$ reacts with free amino-terminal groups to establish a new compound, carbaminohaemoglobin, in both α and β haemoglobin chains. Amino groups are accessible for attachment to N-terminals and also to side-chains of arginine and lysine residues in red blood cells.