Partial pressure reflects the relative amount of gas in a mixture and is measured in millimeters of mercury (mm Hg). Llamas are native to the Andes Mountains in South America. The partial pressure of O₂ (abbreviated P_O₂) in the atmosphere where llamas live is about half of the P_O₂ at sea level. As a result, the PO₂ in the lungs of llamas is about 50 mm Hg, whereas that in human lungs at sea level is about 100 mm Hg. A dissociation curve for hemoglobin shows the percentage of saturation (the amount of O₂ bound to hemoglobin) at increasing values of P_O₂ As you see in the graph below, the dissociation curves for llama and human hemoglobin differ. Compare these two curves and explain how the hemoglobin of llamas is an adaptation to living where the air is 'thin.'

Question

Partial pressure reflects the relative amount of gas in a mixture and is measured in millimeters of mercury (mm Hg). Llamas are native to the Andes Mountains in South America. The partial pressure of O₂ (abbreviated P_O₂) in the atmosphere where llamas live is about half of the P_O₂ at sea level. As a result, the PO₂ in the lungs of llamas is about 50 mm Hg, whereas that in human lungs at sea level is about 100 mm Hg. A dissociation curve for hemoglobin shows the percentage of saturation (the amount of O₂ bound to hemoglobin) at increasing values of P_O₂ As you see in the graph below, the dissociation curves for llama and human hemoglobin differ. Compare these two curves and explain how the hemoglobin of llamas is an adaptation to living where the air is 'thin.'

Graph comparing O2 saturation of hemoglobin in llamas and humans at varying PO2 levels.

Accepted Answer

Hello, everyone and welcome to today's video. So the oxygen disassociation curve of high altitude dear mice hemoglobin is shifted to the left as compared to low altitude deer mice hemoglobin in this context, identify which of the following statements is incorrect. Remember that we're looking for the incorrect statement among our answer choices. Well, before we jump into the problem, I really want us to understand why these oxygen dissociation curved being shifted to the left means. And this is actually going to mean or it's going to result in this hemoglobin having a higher oxygen binding affinity. And this is a result of this high altitude deer mice hemoglobin having an oxygen dissociation curved shifted to the left. Now let's go over our answer choices in order to solve this problem beginning by answer choice. A high altitude D mice hemoglobin has a higher oxygen binding affinity. This is what we saw here. So it is a correct statement and we're going to cancel it out because we're looking for the incorrect one. Then we have answer choice. See the high altitude, your mind's hemoglobin becomes saturated with oxygen at a lower partial pressure of oxygen. This means that it gets saturated with oxygen a lot faster. Or since it has such a high oxygen binding affinity, it is definitely going to be saturated with oxygen faster. So we're going to cancel this out because it is a correct statement. And then we have answer choice. The variation in globin genes which code for hemoglobin appeared to be the cause of increased oxygen binding affinity of the hemoglobin in high altitude, the mice. So remember that we have the same organism and this same organism, there is differences in the hemoglobin of the high altitude and the low altitude mice because this hemoglobin is a protein, it is going to be coded by these DNA by these genes. So this is definitely the cause of why there is these differences in oxygen binding affinity. And this is a correct statement. We're going to cancel it out. This all leaves us with answer choice B the P 50 or just the point at which we have 50% saturation of oxygen in this hemoglobin of low altitude deer mice is lower, which means that just like here it becomes saturated faster. Well, remember the high altitude mice actually has a P 50 that is going to be a lot lower. It is going to be able to become saturated with oxygen a lot faster. So this is actually our incorrect statement because this low altitude the your mice is going to have a very much higher P 50. So we're going to highlight answer choice B as the correct answer to our question. I really hope this video helped you and I hope to see you on the next one.

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Key Concepts

Partial Pressure of Oxygen (PO₂)

Hemoglobin Saturation Curve

Adaptation to Altitude