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16 Cards in this Set
- Front
- Back
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Describe the structure of heme.
How many binding sites are there? Where? What occupies them? |
Fe + protoporphyrin
Fe has 6 binding sites. 4 - occupied by N (from protoporphyrin), 1 - by histidine and ONE OPEN SPOT for O2 |
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Describe the structure of hemoglobin.
What kind of kinetics does Hgb follow? |
Hgb is a tetramer made of 2 alpha units and 2 beta units.
Sigmoidal Kinetics. Binds O2 more easily the more O is bound. |
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Describe the structure of myoglobin.
What kind of kinetics does it follow? |
Myoglobin has a single globin chain = a monomer.
Michaelis-Menten kinetics - holds onto O2 until VERY low PO2 |
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What is one function of albumin as relates to this lecture?
What is one condition caused by low albumin in the blood? |
Creates osmotic pressure - H2O wants to DILUTE these proteins in the blood.
Kwashiorkor = very low serum albumin from no nutrition leads to massive edema. |
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How does 2-3 Bisphosphoglycerate affect O2 transport?
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Stabilizes T state (favors O2 RELEASE)
Pushes curve RIGHT -----> |
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Why does 2-3 Bisphosphoglycerate stabilize the T state?
Is there more or less affinity for O2 with increased 2-3 Bisphosphoglycerate? |
2-3 Bisphosphoglycerate blocks Histidine from the center of the molecule.
LOWERS affinity for O2 = favors T state. |
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How does HgF respond to 2-3 Bisphosphoglycerate?
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HgF has LOW affinity for 2-3 Bisphosphoglycerate....it has MUTED effects does not favor T state so much...HgF gets to keep O2. (Favors R state)
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What does affects does hypoxemia have on gas transport?
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INCREASE 2-3 Bisphosphoglycerate which favors T state (favors oxygen release)
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In general, what does favoring the T state mean for O2 transport?
Which way does the curve push? |
T state is RIGID - does NOT like holding O2. Favors RELEASE of oxygen.
Curve pushes RIGHT. ----> |
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In general what does favoring the R state mean for O2 transport?
Which way does the curve push? |
R = relaxed state - so there is room for O2 to come on board...
Favors O2 UPTAKE. Pushes curve to the left |
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What is the Bohr effect?
Which state is favored? |
Decreased pH (increase H+) results in O2 release from Hgb so Hgb can pick up spare H+'s.
FAVORS T STATE (O2 RELEASE) |
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Increase in temperature favors which state with O2 transport?
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INCREASE TEMPERATURE favors T STATE.
Increasing temp gives Hbg less affinity for O2 - favors its release. |
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Increase in Cl- favors which state?
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NCREASE in chloride ions favors T STATE.
Increasing temp gives Hbg less affinity for O2 - favors its release. |
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What effect does increase in bulky internal anions (which can't cross RBC membrane) have on O2 transport?
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Favors T state. Drives out HCO3-, Cl- in, and OH- (which means [H+] increases in the cell) = favors RELEASE of O2.
Pushes graph to the right ------> |
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What affect does increased [CO2] have on gas transport in RBC's?
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increased CO2 pushes Bohr effect toward dissociation of H2CO3 making more [H+]. HCO3- builds up and leaves RBC. Hb will RELEASE it's O2 and pick up the extra H+ ions.
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What affect does decreased [CO2] have on gas transport in RBC's?
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Decreased CO2 favors association of H+ and HCO3. HCO3 enters cell (so Cl leaves cell). Hbg lets go of H+ to PICK UP O2.
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