Allosteric Effects problems
- 1. The Hill coefficient (nH) for myoglobin and hemoglobin are respectively
Options- A. 2.8 and 1.0
- B. 1.0 and 2.8
- C. 1.2 and 4.5
- D. 4.5 and 1.2 Discuss
Correct Answer: 1.0 and 2.8
- 2. An allosteric activator
Options- A. increases the binding affinity
- B. decreases the binding affinity
- C. stabilizes the R state of the protein
- D. both (a) and (c) Discuss
Correct Answer: both (a) and (c)
- 3. The conformational changes from the T to the R state is initiated by
Options- A. binding of oxygen to the heme
- B. movement of the proximal histidine towards the heme
- C. movement of the F-helix, which contains the proximal His
- D. reorganization of protein-protein contacts between the individual subunits Discuss
Correct Answer: binding of oxygen to the heme
- 4. When protein binds two ligands in a non-cooperative manner, then the x-intercept of the Scatchard Plot is
Options- A. 1
- B. 2
- C. not defined
- D. none of the above Discuss
Correct Answer: 2
- 5. The specificity of a ligand binding site on a protein is based on
Options- A. the absence of competing ligands
- B. the amino acid residues lining the binding site
- C. the presence of hydrating water molecules
- D. the opposite chirality of the binding ligand Discuss
Correct Answer: the amino acid residues lining the binding site
- 6. A protein that binds two ligands in a non-cooperative manner will show
Options- A. a sigmodial binding curve
- B. a hyperbolic binding curve
- C. a linear Scatchard Plot
- D. both (b) and (c) Discuss
Correct Answer: both (b) and (c)
- 7. O2 binding to hemoglobin results in
Options- A. 100-fold higher affinity for the last O2 bound than for the first
- B. extensive protein conformational change
- C. both (a) and (b)
- D. 100-fold lower affinity for the last O2 bound than for the first Discuss
Correct Answer: both (a) and (b)
- 8. In hemoglobin, allosteric effects occur
Options- A. only in humans
- B. for maintaining Fe in the Fe2+ state
- C. to minimize oxygen delivery to the tissues
- D. to maximize oxygen delivery to the tissues Discuss
Correct Answer: to maximize oxygen delivery to the tissues
- 9. Bisphosphoglycerate (BPG) cannot bind to the oxygenated R state of hemoglobin because
Options- A. it is displaced from the heme by oxygen
- B. it is displaced from the heme by movement of the proximal histidine
- C. its binding pocket becomes too small to accommodate BPG
- D. BPG binds to the R state with the same affinity as the T state Discuss
Correct Answer: its binding pocket becomes too small to accommodate BPG
- 10. Small molecules affect hemoglobin (Hb) by
Options- A. decreasing Hb affinity for O2
- B. increasing [H+]
- C. increasing Hb affinity for O2
- D. increasing [H+] and decreasing Hb affinity for O2 Discuss
Correct Answer: increasing [H+] and decreasing Hb affinity for O2
More in Biochemistry:
Programming
Copyright ©CuriousTab. All rights reserved.