Crocodiles can use virtually 100% of the oxygen in its blood, whereas humans canextract only about 65% of the oxygen in their blood. Crocodile hemoglobin (Hb)binds HCO3, rather than 2,3-bisphosphoglycerate (BPG), when in the T-state.Which of the following best explains why HCO3¯ in the crocodile works better than2,3-BPG in humans to help the Hb to release more of its bound oxygen?Crocodile Hb binds more oxygen than human Hb, and so the crocodile has moreoxygen available than humans do.The [HCO3] varies with the amount of oxygen used, whereas the [BPG] inhuman erythrocytes is constant regardless of need.Humans require their hemoglobin to be sensitive to [BPG] in order for HbF (fetalHb) to have a higher affinity for oxygen than maternal Hb.Since crocodile Hb binds HCO3, the HCO3 will not be available to bind to H+(Bohr protons), and so more oxygen will be released to the tissues.Crocodiles are cold-blooded and so do not need as much oxygen as humans; thisis why they can stay under water longer to drown their prey.

Let's evaluate each statement to determine which one best explains why HCO3 in the crocodile works…

Answered: Crocodiles can use virtually 100% of…

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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This graph shows the O2 binding curves of Hemoglobin. Which one is the R-state curve, and which one is the T-state? Why these curves are different comparing to the normal curve (middle one) 1.0 0.8 Observed hemoglobin- binding curve 0.6 0.4 0.2 0.0 50 100 150 200 p02 (torr) Y (fractional saturation)
2,3 BPG is an allosteric effector that decrease haemoglobin affinity for oxygen by stabilizing the T-state of deoxyhaemoglobin. This lead to the release of oxygen to cells and body tissues for use. H atom and CO2 are also allosteric effector and can do same. How?
Which of the following is incorrect about 2,3-bisphosphoglycerate (BPG)? It is highly (-) charged b. It prevents binding of O₂ to hemoglobin Oc. It binds only to the relaxed (oxy) conformation of hemoglobin Od. It binds in the space between the four subunits of hemoglobin a.
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
Hemoglobin and myoglobin both use heme as their prosthetic group and they both bind O2. However, their O2-binding curves indicate these proteins have different activities. What lind of information can be learned about the differences between the curves?
2,3-bisphosphoglycerate (BPG) is a negative allosteric regulator of hemoglobin that is produced in red blood cells. Normally, red blood cell levels of BPG are 5 mmol/L, yielding curve 2. Individuals acclimated to high altitudes can have BPG levels of 8 mmol/L to optimize their oxygen utilization. Saturation 2 3 S Which curve represents hemoglobin of someone living at normal altitudes? 1 2 Pos (mm Hg) 3 None of the answers are correct 2 and 3
Describe how the following allosteric effectors regulated Hemoglobin’s O2 affinity: • CO2• H+ (pH; Explain the basis for the Bohr Effect)• 2,3-BPG • CO
The O2-binding curve for Hemoglobin (Hb) is sigmoidal because: a O2 binding to Hb increases the binding affinity of Hb for additional O2. b The pH of blood is near the pKa of histidine. c The pH of the bloodstream changes with changes in O2 concentration. d Hb’s O2-binding affinity changes with changes in pH.
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 e 0.5 HbA +ВPG 2 4 6 8 10 pO2 (kPa) What is the physiological significance of the different O2 affinities?
1. The diagram on the right compares the O2 binding prop- 1.0 r erties of normal adult hemoglobin (HbA) to those of one dubbed Hb Great-Lakes characterized by the mutation Leu(B68)His. In the dia- gram Y= fraction of heme groups with bound O2, and pO2, the par- tial pressure of O2 above the solution, is measured in units of torr or mmHg. Hb Great Lakes 0.8 Hb A 0.6 Draw the corresponding Hill plot, being careful to reproduce graph- ically the dissociation equilibrium constant for O2 binding (Ko2) for Y each hemoglobin and to show the difference in the extent of allo- stery or cooperativity of subunit interaction in each type of hemo- globin. 0.4 You need draw only the central, linear portion of the Hill plot. 0.2 State what is the likely magnitude of the Hill constant (nH) for HbA from your reading and state what is the likely range of the magni- tude of the Hill coefficient for Hb Great Lakes. 0 10 20 30 40 50 60 pO2 (torr)
Below is the O₂ binding curve for adult Hb in whole blood (containing BPG) shown in red (labelled Hb). Fraction of Hb bound with Oxygen 1.0 0.8 0.6 0.4 0.2 0.0 0 20 40 pO2 (torr) 60 80 ABC c. Which curve lacks cooperativity? [Select] Hb 100 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 p50)? [Select]
Oxygen affinity of fetal blood is higher than that of maternal blood and may help to provide the fetus with an adequate oxygen supply during pregnancy. In mammals, 2, 3-biphosphosphoglycerate (BPG) mediates intracellular hemoglobin function by lowering cxygen affinity. Fetal red blood cells have higher affinity for oxygen because of a smaller effect of BPG on oxygen affinity of fetal hemoglobin (Hb F) compared with adult Hb (Hb A). Which symbol shows the PS0 value corresponding to Hb F? 14 12 10 0.0 0.5 1.0 1.5 2.0 2,3-BPG (mM) O Crcle O Dimond O Square O Triangle (6H ww) d

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