a. Suggest two possible reasons why iron Fe2+ must be incorporated into the heme group, rather than free in the red blood cells? b. Both oxygen and carbon dioxide are bound to hemoglobin Hb. Where are they bound in Hb? What changes in the conformation of Hb do they cause upon binding? c. What triggers the release of 02 in Hb when red blood cells are transported into tissues?

a. Suggest two possible reasons why iron Fe2+ must be incorporated into the heme group, rather than free in the red blood cells? b. Both oxygen and carbon dioxide are bound to hemoglobin Hb. Where are they bound in Hb? What changes in the conformation of Hb do they cause upon binding? c. What triggers the release of 02 in Hb when red blood cells are transported into tissues?

Biology: The Dynamic Science (MindTap Course List)

4th Edition

ISBN:9781305389892

Author:Peter J. Russell, Paul E. Hertz, Beverly McMillan

Publisher:Peter J. Russell, Paul E. Hertz, Beverly McMillan

Chapter46: Gas Exchange: The Respiratory System

Section: Chapter Questions

Problem 9TYK

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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.What is the difference between the 5th and 6 coordination sites in the heme group? b.What is the change of the oxygen dissociation curve represented by hemoglobin before and after dissociation into subunits? Briefly explain why.
People suffering with sickle cell anemia have a structural defect in hemoglobin (HB). The major reason for this structural change is mutation of glutamic acid to valine. This leads to a Exposure of polar amino acids, leading to disintegration of hemoglobin. b Burying of polar amino acids, leading to disintegration of hemoglobin. c Exposure of non-polar amino acids leading to long fiber formation. d Burying of non-polar amino acids thereby increasing hydrophobic interactions and formation of long fibres.
Which is/are false? a. Carbaminohemoglobin is hemoglobin bound to carbon dioxide b. In the lungs, the oxyhemoglobin saturation curve undergoes a 'left shift' c. At a PO2 of 10 mmHg, there is more deoxyhemoglobin in blood that oxyhemoglobin d. Higher temperatures and lower pH cause hemoglobin to bind more readily with oxygen than in conditions of lower temperatures and higher pH
x The Bohr effect describes the impact of changes in serum pH and CO2 concentrations on the oxygen dissociation curve of hemoglobin. This effect is physiologically important because it allows the body to adapt to changing conditions and provide enough oxygen to different types of tissues. **Plot the curves of hemoglobin oxygen saturation for patients in conditions of acidosis (serum pH below 7.34) and alkalosis (serum pH higher than 7.45) and compare it to the one in normal conditions. ** **When tissues, such as muscle tissue, are performing large amounts of strenuous activity the increase in metabolic activity produces CO2 as waste. Once in the bloodstream the enzyme carbonic anhydrase speeds up the conversion of CO2 to bicarbonate and protons. How does this affect the release of oxygen to the tissues?** **2,3-bisphosphoglycerate is an allosteric inhibitor of oxygen binding to hemoglobin. Acclimatization to high altitude involves numerous physiological and biochemical changes,…
d) Determine which statements apply to hemoglobin, myoglobin, or neither (you can write in the corresponding numbers for each statement, as appropriate) Hemoglobin Myoglobin Neither 1. Oxygen binds irreversibly to this molecule.2. This molecule has greater affinity for oxygen.3. The oxygen dissociation curve is sigmoidal in shape.4. Carbon monoxide binds at an allosteric site, lowering oxygen binding affinity.5. The binding pattern for this molecule is considered cooperative.6. This molecule delivers oxygen more efficiently to tissues.7. As oxygen binds to this molecule, the shape of the molecule changes, enhancing further oxygen binding.8. The oxygen dissociation curve is hyperbolic in shape.
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?
The sigmoidal, cooperative binding curve commonly observed for hemoglobin is a result of: a) competition between CO2 and O2 for heme binding. B) competition between heme and distal His for O2 binding c) competition between BPG and CO2 for binding at the central cavity site d) T to R transition Hemoglobin has a tendency to release its oxygen to the tissues because: a) in this region pH is high and O2 concentrations are low b) in this region both pH and O2 concentrations are low c) in this region both pH and O2 concentrations are high d) there is much BPG in this region Which statement about fetal hemoglobin is not true? A) fetal hemoglobin has gamma chains instead of beta chains b) fetal hemoglobin binds BPG less strongly than maternal hemoglobin c) fetal hemoglobin binds oxygen less strongly than maternal hemoglobin d) fetal hemoglobin binds oxygen more strongly than maternal hemoglobin Which process is most responsible for the sickling of cells seen in sickle…
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The partial pressure of oxygen in the venous blood of a human at rest at sea level is approximately 40 torrs a.) Calculate the fractional saturation of hemoglobin under these conditionsb.) What percentage of the oxygen originally bound to hemoglobin in the alveoli remained unreleased?c.) Is the residual oxygen bound to hemoglobin under these conditions of any benefit? Explain
3. When muscles are more active physiological conditions change to affect oxygen binding to Hemoglobin. Briefly describe the changes that occur and why this affects hemoglobin function. Draw the shifted curve on the graph above. A. What physiological conditions change during exercise (levels of what molecules are increasing/decreasing)? B. How do these molecules directly affect Hb’s structure ? What interactions does this stabilize ? C. How do these interactions affect the affinity of Hb for O2? How would this affect the binding curve for Hb? Draw on the graph provided. D. How will this shift in the binding curve affect the function of Hemoglobin ? E.Where does the physiological pO2 in the tissues fall on the O2 binding curve ? In the lungs ? Why is this physiologically important?
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