Exercise on Hemoglobin
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Hemoglobin Exercise

1. O2, CO2, H+, and BPG4- all associate with hemoglobin. Fill in the table below to describe these associations.

Table 1: Solutes that Bind Hemoglobin

O2

CO2

H+

BPG4-

Does it bind heme or globin?

       

Does it stabilize
R or T?

       

number bound per Hb molecule

       

2. Carbonic anhydrase catalyzes this reaction: CO2 + H2O ↔ HCO3- + H+
a. What is the effect on [H+] of increasing [CO2]?
b. What is the effect on hemoglobin conformation of increasing [CO2]?
c. Do H+ and CO2 bind to the same part of a hemoglobin molecule?

3. Draw a graph that shows the percent of hemoglobin sites with bound oxygen as oxygen concentration increases. The line of the graph is line A.
Draw a second line (line B) that shows the effect of increasing the concentration of CO2.
Draw a third line (line C) that shows the effect of increasing CO2 and [H+] together.

4. For the graph in question 3, locate a place on line A where most of the hemoglobin is in the R conformation. Draw a line straight down to indicate the [O2] for that point.
For lines B and C at that oxygen concentration, is most hemoglobin R or T?

 

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