Both myoglobin and hemoglobin can adopt both T and R states. Both myoglobin and hemoglobin bind to oxygen with approximately 100% occupancy at normal atmospheric oxygen levels. Each hemoglobin protein can bind 4 BPG molecules, providing a relative destabilization of the R state. CO2 can covalently bind to the N-termini of hemoglobin to stabilize the T state.

Both myoglobin and hemoglobin can adopt both T and R states. Both myoglobin and hemoglobin bind to oxygen with approximately 100% occupancy at normal atmospheric oxygen levels. Each hemoglobin protein can bind 4 BPG molecules, providing a relative destabilization of the R state. CO2 can covalently bind to the N-termini of hemoglobin to stabilize the T state.

Human Heredity: Principles and Issues (MindTap Course List)

11th Edition

ISBN:9781305251052

Author:Michael Cummings

Publisher:Michael Cummings

Chapter10: From Proteins To Phenotypes

Section: Chapter Questions

Problem 19QP: A person was found to have very low levels of functional beta globin mRNA and therefore very low...

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A person was found to have very low levels of functional beta globin mRNA and therefore very low levels of the beta globin protein. What problems would this cause for assembling functional haemoglobin molecules?
Which of the following is true about the T (tense) -->R (relaxed) transition of hemoglobin? A. The T state of hemoglobin binds oxygen with a higher affinity than the R state. B. The binding of O2 to a subunit T state can cause the transition of other subunits to the R state. C. The T state has a narrower pocket between b subunits than does the R state. D. When hemoglobin undergoes the T--> R transition, the structures of the individual subunits change dramatically.
Which of the following statements is false concerning the structure of hemoglobin? a. The binding of BPG stabilizes the T-state of Hb b. The R-state of Hb is favored under environments of high concentrations of O2 c. Hemoglobin's affinity for oxygen increases as protons ionize from the N-terminal tails d. Hemoglobin is stabilized in the low affinity state in the presence of high concentration of protons e. Hemoglobin favors the R-state in basic environments
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
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?
In addition to O2 binding, changes in other chemical conditions can result in changes in hemoglobin structure and function. Increases in blood H+ result in oxygen binding curves for hemoglobin that are shifted to the right. The effect of H+ can be understood in terms of the equilibrium:H-Hb+ + O2 → Hb-O2 + H+How does the difference in pH in the lungs and tissues help hemoglobin do its job of delivering oxygen? Use the equilibrium equation in your argument.
Myoglobin ... A. has higher affinity for O2 than hemoglobin does. B. consists of four polypeptide chains, just as hemoglobin does. C. has a lower affinity for O2 than hemoglobin does. D. is found in the interstitial fluids, in contrast to hemoglobin that is found in red blood cells. E. can bind four O2 molecules at once.
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?
Sickle-cell hemoglobin (HbS) differs from normal human adult hemoglobin (HbA) by a single mutational change, Glu6 S Val, which causes the HbS molecules to aggregate under proper conditions. Under certain conditions, the HbS filaments that form at body temperature disaggregate when the temperature is lowered to 0°C. Explain.
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 of the following statements is INCORRECT about how the components of hemoglobin are recycled? a. Iron ions are either stored in a phagocytic cell or circulate in the blood, bound to transferrin (a plasma protein). b. Each heme is stripped of its iron and converted to bilirubin, then excreted in bile. c. The alpha and beta chains are released into the bloodstream for use by other cells. d. Hemoglobin can be recycled only if phagocytized by macrophages.
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