Q. No.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
A large proportion of oxygen is left unsused in the human blood even after its uptake by the body tissues. This
1. raises the of blood to 75 mm of Hg
2. is enough to keep oxyhaemoglobin
3. helps in releasing more to the epithelial tissues
4. acts as a reserve during muscular exercise
What is true about RBCs in humans?
| 1. | They carry about 20-25 percent of |
| 2. | They transport 99.5 percent of |
| 3. | They transport about 80 percent oxygen only and the rest 20 percent of it is transported in a dissolved state in blood plasma |
| 4. | They do not carry at all |
Oxygen binding to haemoglobin in blood is
| 1. | directly proportional to the concentration of CO2 in the medium |
| 2. | inversely proportional to the concentration of CO2 in the medium |
| 3. | directly proportional to the concentration of CO in the medium |
| 4. | independent of the concentration of CO in the medium |
Identify the wrong statement with reference to the transport of oxygen.
| 1. | Partial pressure of CO2 can interfere with O2 binding with haemoglobin. |
| 2. | Higher H+ conc. in alveoli favours the formation of oxyhaemoglobin. |
| 3. | Low pCO2 in alveoli favours the formation of oxyhaemoglobin. |
| 4. | Binding of oxygen with haemoglobin is mainly related to partial pressure of O2. |
Asthma may be attributed to?
1. allergic reaction of the mast cells in the lungs
2. inflammation of the trachea
3. accumulation of fluid in the lungs
4. bacterial infection of the lungs
Match the following columns and select the correct option :
| Column I | Column II | ||
| (a) | Pneumotaxic centre | (i) | Alveoli |
| (b) | O2 dissociation curve | (ii) | Pons region of the brain |
| (c) | Carbonic anhydrase | (iii) | Haemoglobin |
| (d) | Primary site of exchange of gases | (iv) | R.B.C. |
| (a) | (b) | (c) | (d) | |
| 1. | (i) | (iii) | (ii) | (iv) |
| 2. | (ii) | (iii) | (iv) | (i) |
| 3. | (iii) | (ii) | (iv) | (i) |
| 4. | (iv) | (i) | (iii) | (ii) |
Transport of gases in alveoli takes place by:
| 1. Active transport | 2. Passive transport |
| 3. Simple diffusion | 4. None of the above |
People living at sea level have around 5 million RBC per cubic millimeter of their blood whereas those living at an altitude of 5400 metres have around 8 million. This is because at high altitude:
1. people get pollution-free air to breathe and more oxygen is available
2. atmospheric O2 level is less and hence more RBCs are needed to absorb the required amount of O2 to survive
3. there is more UV radiation which enhances RBC production
4. people eat more nutritive food, therefore more RBCs are formed
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