Respiration and Gas Transport

Oxygen binding curve for myoglobin is hyperbolic, which reflects non-cooperative binding.

At high altitudes, lower oxygen pressure stimulates increased erythropoietin production, causing polycythemia - elevated RBC and hemoglobin concentration. This gives skin a rosy appearance. Option A is incorrect because hemoglobin affinity actually decreases (right shift of oxygen dissociation curve) to facilitate oxygen release to tissues. Option C is not the primary physiological adaptation.

Haemoglobin (Hb) is a transport protein that carries oxygen in the blood. It is necessary because oxygen is not very soluble in water - most part of the blood is water. Each Hb is capable of binding a total of 4 oxygen molecules (one molecule per subunit).

Approximately 98.5% of oxygen in blood is bound to hemoglobin, with only about 1.5% dissolved in plasma. This high hemoglobin binding capacity makes red blood cells efficient oxygen transporters.

Each haemoglobin molecule contains four iron-containing heme groups, and each heme can bind one oxygen molecule. Therefore, one haemoglobin molecule carries four oxygen molecules.

Carbon monoxide (CO) binds to haemoglobin with approximately 200-250 times greater affinity than oxygen, forming carboxyhaemoglobin. This stable complex is the strongest bond among the options, which is why CO is so toxic.

Respiration is fundamentally about energy liberation - the process where cells use oxygen to break down glucose and release ATP energy. While oxygen intake and CO2 release occur during respiration, they are means to the end of energy production. Options A, B, and C describe only parts of the process.

CO2 is transported in blood as carbaminohemoglobin (HbCO2) when bound to hemoglobin's amino groups. This accounts for about 20-30% of CO2 transport. NaHCO3 (sodium bicarbonate) is the main transport form (70%), H2CO3 is carbonic acid (transient), and HbCO is carbon monoxide bound to hemoglobin (a toxin, not normal CO2 transport).

This is the correct answer as both these statements are correct. Carbon dioxide and urea are two waste products of the human body that are produced by the human cells. Some organisms store wastes in body parts.

This is the correct answer as all the given statements are correct.

This is the correct option. When inhaled, carbon monoxide combines with the hemoglobin of our blood and reduces blood's oxygen carrying capacity.

Carbon monoxide binds to hemoglobin in red blood cells to form carboxyhaemoglobin, which is extremely stable (200+ times stronger bond than oxyhemoglobin). This prevents oxygen transport, causing CO poisoning. CO does not form nitro-haemoglobin, carbon dioxide haemoglobin, or oxy-haemoglobin.

ANS 4.

Oxygenated blood has picked up oxygen from the lungs and carries it to body tissues. It is bright red and contains relatively more oxygen than deoxygenated blood, which has delivered its oxygen to tissues and is returning to the lungs.