Below is the O2 binding curve for adult Hb in whole blood (containing BPG) shown in red (labelled Hb). Hb 20 40 60 80 100 pO2 (torr) a. Which curve is the best representation for stripped Hb (pure hemoglobin with heme, but no other small allosteric molecules associated)? [ Select] b. Which curve has the lowest affinity (as measured by the pso)? [ Select ] c. Which curve lacks cooperativity?( Select ] Fraction of Hb bound with Oxygen 0.2 0.4 0.6 0.8 0'0 |||

Below is the O2 binding curve for adult Hb in whole blood (containing BPG) shown in red (labelled Hb). Hb 20 40 60 80 100 pO2 (torr) a. Which curve is the best representation for stripped Hb (pure hemoglobin with heme, but no other small allosteric molecules associated)? [ Select] b. Which curve has the lowest affinity (as measured by the pso)? [ Select ] c. Which curve lacks cooperativity?( Select ] Fraction of Hb bound with Oxygen 0.2 0.4 0.6 0.8 0'0 |||

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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Similar questions

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?
Which hemoglobin has a higher affinity for O2 at the tissue pO2 of around 4 kPa?
From the figure of O2 binding to myoglobin and hemoglobin (ignore the linemarked as T) as described in lecture (shown below) answer the following questions. a) Estimate the P50 for myoglobin from the plot. Show how this estimation isdetermined from the binding curve above. ( The first ghraph) b)Using YO2 = PO2/P50 + PO2 , calculate the fraction of O2 bound for myoglobin at 1 torr. (2nd graph) c)Using the binding curve on the previous page, show how you can estimate whatfraction of hemoglobin is bound near tissues at a pO2 of 30 torr and provide this value. If the pH were lowered, will the amount of O2 bound to hemoglobin at 30 torr increaseor decrease? Explain why this is so based on how this changes hemoglobin structure. If 2,3-BPG were added to the solution, will the amount of O2 bound to hemoglobin at30 torr increase or decrease? Explain why this is so based on how this changes hemoglobinstructure.
Compared to adult Hb (HbA), fetal Hb (HbF) has one less histidine in the central cavity where BPG binds. What is the consequence of this difference in the P50 value? a The P50 value of HbF approaches zero torr at high O2 partial pressures. b The P50 value of HbF approaches 100 torr at high O2 partial pressures. c HbA has a smaller P50 value compared to HbF d HbF and HbA have the same P50 value. e HbF has a smaller P50 value compared to HbA
Will a mutation from Distal histidine to phenylalanine shift the binding curve of hemoglobin?Will it shift the curve to the left or right, shift to myoglobin or no longer bind to O2?
Give typed explanation Which of the following effects is NOT true? If stripped Hb is treated with 2,3-BPG, the O2-binding curve for Hb will shift left. If stripped Hb is treated with 2,3-BPG and CO2, the O2-binding curve for Hb will mirror that of fully intact Hb. If stripped Hb is treated with CO2, the O2-binding curve for Hb will shift right. All of the listed effects are true.
) Dr Merrick is so excited to know the affinity constant Kd values for O2 binding to mammoth OBP and elephant hemoglobin at pH=7, that he starts speculating about the kinetics of binding to O2. If the ka value of mammoth EHb-O2 complex was the same as the ka value of mammoth OBP-O2 complex, what would be the ratio between the kd values of these complexes? Explain your reasoning. Hint: we are looking for the ratio kd(EHb)/kd(OBP) at pH=7.
Determine the Hill coefficient, n, for myoglobin (Mb), hemoglobin (Hb), and recombinant hemoglobin (HbX). Given the results of the Hill plot and the dissociation curves, which of the following are true? Oxygen binding by HbX is less cooperative than for Hb The Hill coefficient for Hb is equal to the number of hemoglobin O2 binding sites Oxygen binding by Hb is less cooperative than for Mb. HbX will load less O2 in the lungs and unload less O2 in active tissues than normal Hb.
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
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
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.
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…