Question

The bulk of carbon dioxide is carried chemically combined with the amino acids of hemoglobin as carbaminohemoglobin in the RBCs. The bulk of carbon dioxide is carried chemically combined with the amino acids of hemoglobin as carbaminohemoglobin in the RBCs. True False

Answer 1

The statement is false since the majority of CO2 in the blood is carried as bicarbonate ions (85%), not as carbaminohemoglobin. Only 20% of CO2 is transported as carbaminohemoglobin, and a smaller amount is simply dissolved in the plasma.

Step-by-step explanation:

The statement provided by the student is false because the bulk of carbon dioxide in the blood is not transported as carbaminohemoglobin but rather as bicarbonate ions. Approximately 85 percent of carbon dioxide is transported in this way, via the bicarbonate buffer system. Carbon dioxide diffuses into red blood cells and is quickly converted into carbonic acid with the help of the enzyme carbonic anhydrase (CA). This carbonic acid then dissociates into bicarbonate (HCO3-) and hydrogen ions (H+). The bicarbonate is then exchanged for chloride ions through the chloride shift and transported in the plasma.

Only about 20 percent of carbon dioxide is bound by hemoglobin in the form of carbaminohemoglobin. This occurs when carbon dioxide binds to amino acid moieties on the globin portions of hemoglobin, and this form is transported to the lungs. Furthermore, a smaller portion of carbon dioxide, about 5 to 7 percent, is transported dissolved in the plasma.

Answer 2

Answer: True

Explanation:Carbon dioxide is transported is transfer in 3 basic ways to human cells.

About 20 % of C0 2 is transported as Carbaminohemoglobin to reach the lungs carbon dioxide binds directly to the amino acid moieties on the globin portions of the haemoglobin to form carbaminohemoglobin. This is a reversible reaction as shown below.

CO2 + Hb ↔ HbCO2.

The reversible binding of C02 to the haemoglobin is due to the the partial pressure of carbondioxde. In the lungs the partial pressure of C02 is low. Therefore C02 is unbounded from the HB and leaves in the lungs, thus the blood leaving the lungs for the body tissues has low partial pressure C02. Compare to the blood in the tissues with high partial pressure of C02 from metabolic activities of cellular respiration. The C02 therefore diffuses from the tissues to bind with HB to form Carbaminoheamologbin.

In addition C02 is transported by other means.

1. As bicarbonate 70% of the Co2 in the blood is transported and bicarbonate buffer.

CO2 + H2O CA ↔ H2CO3↔H+ + HCO3

2, As soluble carbon dioxide which dissolves directly in to the blood stream; this is about 7-10%