Humans are not able to survive for long periods at very high altitudes primarily because:
| 1. | The oxygen content is very low with respect of that found at sea level. |
| 2. | The carbon dioxide is much more than that found at sea level. |
| 3. | The partial pressure of oxygen is very low than that found at sea level. |
| 4. | The atmospheric pressure is much higher than that found at sea level, which makes the amount of oxygen available one-fourth that found at sea level. |
The chloride shift is also known as Hamburger phenomenon and it
1. occurs primarily in pulmonary capillaries.
2. occurs when Cl- replace HCO3- within red blood cells.
3. decreases the formation of bicarbonate ions.
4. decreases the number of hydrogen ions.
The haemoglobin of a human foetus
| 1. | has a lower affinity for oxygen than that of the adult |
| 2. | has the same affinity for oxygen as that of an adult |
| 3. | has only 2 protein subunits instead of 4 |
| 4. | has a higher affinity for oxygen than that of an adult |
When a man inhales air containing normal concentration of O2 as well as CO he suffers from suffocation because
| 1. | CO reacts with , reducing its percentage in air |
| 2. | haemoglobin combines with CO instead of and forms carboxyhaemoglobin |
| 3. | CO affects diaphragm and intercostal muscles |
| 4. | CO affects the nerves of the lungs |
Given below are two statements:
| Assertion (A): | Nitric oxide transport by hemoglobin to peripheral tissues is hypothesized to assist oxygen transport in tissues. |
| Reason (R): | Nitric oxide can also be transported by hemoglobin bound to specific thiol groups in the globin protein. |
| 1. | Both (A) and (R) are true and (R) is the correct explanation of (A). |
| 2. | Both (A) and (R) are true but (R) is not the correct explanation of (A). |
| 3. | (A) is true but (R) is false. |
| 4. | Both (A) and (R) are false. |