Which statements are true/false ?
(i) Blood transports CO2 comparatively easily because of its high solubility
(ii) Approximately 8.9% of CO2 is transported dissolved in plasma
(iii) CO2 diffuses into blood, passes into RBCs and reacts with water to form H2CO3
(iv) Oxyhaemoglobin of erythrocytes is basic
(v) Chloride ions diffuse from plasma into erythrocytes to maintain ionic balance
Which statements are true/false ?
(i) Blood transports CO2 comparatively easily because of its high solubility
(ii) Approximately 8.9% of CO2 is transported dissolved in plasma
(iii) CO2 diffuses into blood, passes into RBCs and reacts with water to form H2CO3
(iv) Oxyhaemoglobin of erythrocytes is basic
(v) Chloride ions diffuse from plasma into erythrocytes to maintain ionic balance
The correct option is D (i),(iii) and (v) are true, (ii) and (iv) are false
True statements:
Statement (i): Blood transports CO2 comparatively easily because of its high solubility
Due to the high solubility of the CO2 in water, the CO2 readily dissolves in water present in blood to form carbonic acid which then dissociates H+ and HCO3− (bicarbonate) ions. Majority of the bicarbonate ions move into the blood plasma and combine with metal ions and are transported in solution in the form of bicarbonate salts.
Hence statement (i) is true.
Statement (iii): CO2 diffuses into blood, passes into RBCs and reacts with water to form H2CO3
The CO2 that is present in the tissues diffuses into the RBCs and reacts with the water in presence of the enzyme carbonic anhydrase to form carbonic acid. And this carbonic acid dissociates into bicarbonate ions (HCO3−) and H+ ions. Hence statement (iii) is true.
Statement (v): Chloride ions diffuse from plasma into erythrocytes to maintain ionic balance.
The carbonic acid formed in the RBCs dissociates into H+ and HCO3− (bicarbonate) ions. Only a small amount of these bicarbonate ions are transported by the RBCs and most of it comes out of the RBCs into the plasma. Movement of HCO3− ions into the blood plasma disturbs the ionic balance between the RBCs and the blood plasma. To restore this balance, chloride ions (Cl−) from the plasma diffuse into the RBCs. This is known as the chloride shift. Hence statement (v) is true.
Statement (ii): Approximately 8.9% of CO2 is transported dissolved in plasma.
∙The transport of CO2 in the blood is as follows;
∙Almost 70% of CO2 is transferred as bicarbonate ions (HCO3-).
∙About 20−25% of CO2 is transported as carbaminohaemoglobin (HbCO2) by RBCs.
∙And only 5−7% of CO2 is dissolved in the plasma of the blood.
Statement (iv): Oxyhaemoglobin of erythrocytes is basic.
Oxyhaemoglobin in erythrocytes is a strong acid which dissociates and releases H+ ions if the blood pH becomes basic. Hence, statement (iv) is false.
True statements:
Statement (i): Blood transports CO2 comparatively easily because of its high solubility
Due to the high solubility of the CO2 in water, the CO2 readily dissolves in water present in blood to form carbonic acid which then dissociates H+ and HCO3− (bicarbonate) ions. Majority of the bicarbonate ions move into the blood plasma and combine with metal ions and are transported in solution in the form of bicarbonate salts.
Hence statement (i) is true.
Statement (iii): CO2 diffuses into blood, passes into RBCs and reacts with water to form H2CO3
The CO2 that is present in the tissues diffuses into the RBCs and reacts with the water in presence of the enzyme carbonic anhydrase to form carbonic acid. And this carbonic acid dissociates into bicarbonate ions (HCO3−) and H+ ions. Hence statement (iii) is true.
Statement (v): Chloride ions diffuse from plasma into erythrocytes to maintain ionic balance.
The carbonic acid formed in the RBCs dissociates into H+ and HCO3− (bicarbonate) ions. Only a small amount of these bicarbonate ions are transported by the RBCs and most of it comes out of the RBCs into the plasma. Movement of HCO3− ions into the blood plasma disturbs the ionic balance between the RBCs and the blood plasma. To restore this balance, chloride ions (Cl−) from the plasma diffuse into the RBCs. This is known as the chloride shift. Hence statement (v) is true.
Statement (ii): Approximately 8.9% of CO2 is transported dissolved in plasma.
∙The transport of CO2 in the blood is as follows;
∙Almost 70% of CO2 is transferred as bicarbonate ions (HCO3-).
∙About 20−25% of CO2 is transported as carbaminohaemoglobin (HbCO2) by RBCs.
∙And only 5−7% of CO2 is dissolved in the plasma of the blood.
Statement (iv): Oxyhaemoglobin of erythrocytes is basic.
Oxyhaemoglobin in erythrocytes is a strong acid which dissociates and releases H+ ions if the blood pH becomes basic. Hence, statement (iv) is false.
5% of CO2 is dissolved in ___(i)____. Another form in which CO2 is transported is when it combines with hemoglobin and this form is called ___(ii)____hemoglobin. CO2 entering the erythrocytes reacts with water to form carbonic acid in the presence of ____(iii)_____. Carbonic acid is an intermediate step; it dissociates to form a hydrogen ion (H+) from the carbonic acid, leaving___(iv)____ dissolved in the blood.
