Studies of oxygen transport in pregnant mammals show that the O2-saturation curves of fetal and maternal blood are markedly different when measured under the same conditions. Fetal erythrocytes contain a structural variant of hemoglobin, HbF, consisting of two a and two y (a2 y2), whereas maternal erythrocytes contains HbA (a2 B2). 1.0 ·HbF +BPG 0.5 HbA +ВPG 2 4 6 8 10 pO2 (kPa) Which hemoglobin has a higher affinity for oxygen under physiological conditions, HbA or HbF? Explain. b. What is the physiological significance of the different O2 affinities?

Studies of oxygen transport in pregnant mammals show that the O2-saturation curves of fetal and maternal blood are markedly different when measured under the same conditions. Fetal erythrocytes contain a structural variant of hemoglobin, HbF, consisting of two a and two y (a2 y2), whereas maternal erythrocytes contains HbA (a2 B2). 1.0 ·HbF +BPG 0.5 HbA +ВPG 2 4 6 8 10 pO2 (kPa) Which hemoglobin has a higher affinity for oxygen under physiological conditions, HbA or HbF? Explain. b. What is the physiological significance of the different O2 affinities?

Human Physiology: From Cells to Systems (MindTap Course List)

9th Edition

ISBN:9781285866932

Author:Lauralee Sherwood

Publisher:Lauralee Sherwood

Chapter11: The Blood

Section: Chapter Questions

Problem 1SQE

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Studies of oxygen transport in pregnant mammals show that the O2-saturation curves of fetal and maternal blood are markedly different when measured under the same conditions. Fetal erythrocytes contain astructural variant of hemoglobin, HbF, consisting of two α and two γ subunits (α2 γ2 ), whereas maternal erythrocytes contain HbA (α2β2).(a) Which hemoglobin has a higher affinity for oxygen under physiological conditions, HbA or HbF? Explain.(b) What is the physiological significance of the different O2 affinities?(c) When all the BPG is carefully removed from samples of HbA and HbF, the measured O2 -saturation curves (and consequently the O2 affinities) are displaced to the left. However, HbA now has a greater affinity for oxygen than does HbF. When BPG is reintroduced, the O2 -saturation curves return to normal, as shown in the graph. What is the effect of BPG on the O2 affinity of hemoglobin? How can the above information be used to explain the different O2 affinities of fetal and…
Studies of oxygen transport in pregnant mammals have shown that the O2-saturation curves of fetal and maternal blood are markedly different when measured under the same conditions. Fetal erythrocytes contain a structural variant of hemoglobin, HbF, consisting of two γ and two β subunits (γ2β2), whereas maternal erythrocytes contain HbA (α2β2). (a) Which hemoglobin has a higher affinity for oxygen under physiological conditions, HbA or HbF? Explain. (b) What is the physiological significance of the different O2 affinities? (c) When all the BPG is carefully removed from samples of HbA and HbF, the measured O2-saturation curves (and consequently the O2 affinities) are displaced to the left. However, HbA now has a greater affinity for oxygen than does HbF. When BPG is reintroduced, the O2-saturation curves return to normal, as shown in the graph. What is the effect of BPG on the O2 affinity of hemoglobin? How can the above information be used to explain the different O2 affinities of…
Under appropriate conditions, hemoglobin dissociates into its four subunits. The isolated α subunit binds oxygen, but the O2 -saturation curve ishyperbolic rather than sigmoid. In addition, the binding of oxygen to the isolated α subunit is not affected by the presence of H+, CO2 , or BPG. What do these observations indicate about the source of the cooperativity in hemoglobin?
Comparison of Fetal and Maternal Hemoglobins.Studies of oxygen transport in pregnant mammals show that the O2-saturation curves of fetal and maternal blood are markedly different when measured under the same conditions. Fetal erythrocytes contain a structural variant of hemoglobin, HbF, consisting oftwo a and two g subunits (α2γ2), whereas maternal erythrocytes contain HbA (α2β2). a)Which hemoglobin has a higher affinity for oxygen under physiological conditions, HbA or HbF? Explain. b)What is the physiological significance of the different O2 affinities? c)When all the BPG is carefully removed from samples of HbA and HbF, the measured O2-saturation curves (and consequently the O2affinities) are displaced to the left. However, HbA now has a greater affinity for oxygen than does HbF. When BPG is reintroduced, the O2-saturation curves return to normal, as shown in the graph. What is the effect of BPG on the O2affinity of hemoglobin? How can the above information be used…
After spending a day or more at high altitude (with an oxygen partial pressure of 75 torr), the concentration of 2,3- bisphosphoglycerate (2,3-BPG) in red blood cells increases. What effect would an increased concentration of 2,3-BPG have on the oxygen-binding curve for hemoglobin? Why would this adaptation be beneficial for functioning well at high altitude?
Increasing concentrations of either 2,3-bisphosphoglycerate (BPG) or protons (H +) cause a ____________ ( rightward OR leftward) shift of the hemoglobin/oxygen binding curve. However, the mechanisms by which these two substances mediate this effect are distinct. Compare & contrast the way by which BPG and protons interact with hemoglobin and thereby influence its structure and function
a) How does the fetal hemoglobin differ from the maternal hemoglobin in regards to structure and function? b) Explain the Bohr effect by drawing oxygen dissociation curves on a single graph that highlight changes in the hemoglobin affinity for O2 c) Describe the molecular basis of sickle cell anemia. Be specific
What is the role of 2, 3-Bisphosphoglycerate (2,3-BPG) in the function of haemoglobin as an oxygen carrier molecule? Explain the binding mechanism and effect of 2,3-BPG leading to the reduced oxygen binding affinity for haemoglobin and transitions in the T (deoxygenated) and R (oxygenated) states of haemoglobin.
Which hemoglobin has a higher affinity for O2 at the tissue pO2 of around 4 kPa?
The following graph shows partial saturation (Y) of myoglobin (Mb), adult hemoglobin (HbA) and fetal hemoglobin (HbF) as a function of partial oxygen pressure (in mmHg). Use it to answer the question: Fetal hemoglobin ( biological function: HbF) demonstrates lower p50 than adult hemoglobin (HbA). This adaptation has the following A. Allow fetal hemoglobin form pentamer subunits. B. HbF has lower affinity for for O2 compared to adult Hb C. Allow fetal hemoglobin to effectively intercept oxygen from mother's hemoglobin. D. Allow fetal hemoglobin to replace myoglobin in muscles
A patient carrying a mutant form of hemoglobin (KD = 48 torr) is planning to take part in a hiking trip that involves strenuous physical activity at ~10,000 feet above sea level. The mutant hemoglobin has reduced oxygen binding cooperativity (n = 2.2) and displays no major structural abnormalities. a. Calculate the percent saturation of hemoglobin in the lungs (pO2 = 70 torr at this elevation) for this patient and for an individual carrying a normal version of hemoglobin b. Calculate the percent saturation of hemoglobin in active skeletal muscle tissue (pO2 = 15 torr) for this patient and for an individual carrying a normal version of hemoglobin c. Will this patient transport oxygen from the lungs to active muscle tissues more or less efficientlythan an individual with a normal version of hemoglobin on this trip? Briefly explain your answer
3A.Describe the difference in biological func on of myoglobin and hemoglobin in the body. How does hemoglobin’s sigmoidal O2 binding curve contribute to its biological func on?( Think binding affinity) 3B. Describe the different ways in which the affinity of oxygen to hemoglobin can be modified in vivo