Biochemistry MCQ Quiz Hub

1. The conformational changes from the T to the R state is initiated by
binding of oxygen to the heme
movement of the proximal histidine towards the heme
movement of the F-helix which contains the proximal His
reorganization of protein-protein contacts between the individual subunits

2. An allosteric activator
increases the binding affinity
decreases the binding affinity
stabilizes the R state of the protein
both (a) and (c)

3. Bisphosphoglycerate (BPG) cannot bind to the oxygenated R state of hemoglobin because
it is displaced from the heme by oxygen
it is displaced from the heme by movement of the proximal histidine
its binding pocket becomes too small to accommodate BPG
BPG binds to the R state with the same affinity as the T state

4. The Hill coefficient (nH) for myoglobin and hemoglobin are respectively
2.8 and 1.0
1.0 and 2.8
1.2 and 4.5
4.5 and 1.2

5. When protein binds two ligands in a non-cooperative manner then the x-intercept of the Scatchard Plot is
1
2
not defined
none of the above

6. O2 binding to hemoglobin results in
100-fold higher affinity for the last O2 bound than for the first
extensive protein conformational change
both (a) and (b)
100-fold lower affinity for the last O2 bound than for the first

7. In hemoglobin allosteric effects occur
only in humans
for maintaining Fe in the Fe2+ state
to minimize oxygen delivery to the tissues
to maximize oxygen delivery to the tissues

8. A protein that binds two ligands in a non-cooperative manner will show
a sigmodial binding curve
a hyperbolic binding curve
a linear Scatchard Plot
both (b) and ©

9. Small molecules affect hemoglobin (Hb) by
decreasing Hb affinity for O2
increasing [H+]
increasing Hb affinity for O2
increasing [H+] and decreasing Hb affinity for O2

10. A protein that shows infinite cooperative for binding of n ligands will.
show a Hill coefficient (nH) of 0.0
only be found in either the unliganded form or the fully liganded form
show a Hill coefficient (nH) of n
both (b) and c

11. The specificity of a ligand binding site on a protein is based on
the absence of competing ligands
the amino acid residues lining the binding site
the presence of hydrating water molecules
the opposite chirality of the binding ligand