Term
| Describe Noncooperative Binding |
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Definition
| The binding of a ligand has no effect of the binding of subsequent ligands. Ie binding of oxygen molecule in myoglobin does not affect binding of other molecules since myoglobin only binds one molecule. |
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Term
| Describe Cooperative Binding |
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Definition
| Cooperative binding refers to the binding of a ligand to a particular site that enhances the binding of subsequent ligands on the same molecule. Binding of one oxygen molecule facilitates the binding of the other 3 molecules to hemoglobin. |
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Term
| What are the characteristic oxygen saturation curves for myoglobin and hemoglobin |
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Definition
Myoglobin = hyperbolic Hemoglobin = sigmoidal The P50 of myglobin is 2.8 The P50 of hemoglobin is 26 P50 refers to the partial pressure of oxygen when the protein is half saturated. |
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Term
| Which hemoglobin chains are dominant during the first 6 weeks of fetal development |
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Definition
alpha, gamma, epsilon, delta epsilon and delta begin to drop off after six weeks. Alpha and gamma continue to be dominant until birth, when gamma drops significantly. Alpha continues thru lifetime |
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Term
| What is the significance of the gamma chain of hemoglobin in fetal blood? |
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Definition
The gamma chain binds oxygen more efficiently than beta chain. Gamma chains drops significantly after birth and beta chain is a dominant chain. The two dominant chain during adulthood are alpha and beta |
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Term
| Carbon dioxide is transported in two forms. What are they and what percentage of CO2 is transported in these forms? |
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Definition
HCO 3- (~80% to lungs) Carbamate (bound to hemoglobin) |
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Term
Describe the binding CO to hemoglobin |
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Definition
CO binds to hemoglobin more tightly than oxygen )~220). Binding to one site of hemoglobin converts it to the Relaxed stated, allowing the subsequent oxygen molecules to bind more tightly to the hemoglobin. Hence, less oxygen is available for delivery to tissues. Carbon dioxide binds to the amino groups of hemoglobin, while CO binds directly to the iron sites. |
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Term
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Definition
In presence of increasing partial pressure of carbon dioxide or decreasing pH, Oxygen loses its affinity for hemoglobin, thus oxygen unloading in the tissues is enhanced. Deoxyhemoglobin has a higher affinity for protons than does hemoglobin. |
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Term
| Describe the binding effect of 2,3 bisphosphoglycerol |
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Definition
Binding of 2,3 bisphosphogycerol to hemoglobin converts it to the T state, thus decreasing oxygen's affinity for hemoglobin. Oxygen unloading in the tissue is enhanced. Normal level of 2,3 BPG in blood is ~5mmol In people adapted to high altitudes ~8mmol Inc'd levels of 2,3 BPG cause oxygen saturation curve to shift to the right. Dec'd levels cause shift to the left. |
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Term
True/False The beta chain of hemoglobin closely resembles the single chain of myoglobin |
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Definition
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