Question

5. Drinking a few drops of a commercial preparation called “vitamin O,” which consists of oxygen and sodium chloride dissolved in water, is claimed to increase the concentration of oxygen in the body. (a) Use your knowledge of oxygen transport to evaluate this claim. (b) Would vitamin O be effective if it were infused directly into the bloodstream?

6. Explain why long-distance runners prefer to train at high altitude even when the race is to be held at sea level. Why must the runners spend more than a day or two at the higher elevation?

9. Hemoglobin S homozygotes who are severely anemic often have elevated levels of BPG in their erythrocytes. Is this a beneficial effect?

21. In active muscles, the pO2 may be 10 torr at the cell surface and 1 torr at the mitochondria (the organelles where oxidative metabolism occurs). Use Eq. 7-6 to show how myoglobin (p50 = 2.8 torr) facilitates the diffusion of O2 through these cells.

25. In humans, the urge to breathe results from high concentrations of CO2 in the blood; there are no direct physiological sensors of blood pO2. Skin-divers often hyperventilate (breathe rapidly and deeply for several minutes) just before making a dive in the belief that this will increase the O2 content of their blood. (a) Does it do so? (b) Use your knowledge of hemoglobin function to evaluate whether this practice is useful.

26. The crocodile, which can remain under water without breathing for up to 1 h, drowns its air-breathing prey and then dines at its leisure. An adaptation that aids the crocodile in doing so is that it can utilize virtually 100% of the O2 in its blood, whereas humans, for example, can extract only ∼65% of the O2 in their blood. Crocodile Hb does not bind BPG. However, crocodile deoxyHb preferentially binds HCO3−. How does this help the crocodile obtain its dinner?

Answer 1

Answer 5:

(a) Regarding the Oxygen transport mechanism that occurs in the body, it is less likely to happen that Vitamin O would increase the oxygen concentration in the body as the body absorbs the oxygen when sufficient haemoglobin is present in the body and also it is very much based on the oxygen-carrying ability offered by the haemoglobin molecule that binds with the oxygen. There are certain factors like Carbon dioxide levels, temperature, environmental factors, pH of the blood, and certain diseases etc. that would affect the oxygen-carrying capacity and delivery of haemoglobin. And most importantly, the extraction of oxygen occurs through the lungs not by the gastrointestinal tracts that can lead to elevate the concentration of oxygen in the blood.

(b) The high concentration of oxygen even if introduced into the bloodstream cannot possibly make a difference as in vertebrate system (ex; humans) the criteria for binding the oxygen is haemoglobin which possess the ability to bind oxygen in a certain way (i.e. it has four subunits and can bind only 4 oxygen molecules not more than that). So, by increasing the amount of vitamin O would not make a remarkable or meaningful difference in the body of an organism.