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Allosteric Effects Online Exam Quiz

Important questions about Allosteric Effects. Allosteric Effects MCQ questions with answers. Allosteric Effects exam questions and answers for students and interviews.

1. A protein that shows infinite cooperative for binding of n ligands will

Options

A : show a Hill coefficient (n H ) of 0.0

B : only be found in either the unliganded form or the fully liganded form

C : show a Hill coefficient (n H ) of n

D : both (b) and (c)

1. The Hill coefficient (n H ) 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

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)

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

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

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

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)

7. O 2 binding to hemoglobin results in

Options

A : 100-fold higher affinity for the last O 2 bound than for the first

B : extensive protein conformational change

C : both (a) and (b)

D : 100-fold lower affinity for the last O 2 bound than for the first

8. In hemoglobin, allosteric effects occur

Options

A : only in humans

B : for maintaining Fe in the Fe 2+ state

C : to minimize oxygen delivery to the tissues

D : 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

10. Small molecules affect hemoglobin (Hb) by

Options

A : decreasing Hb affinity for O 2

B : increasing [H + ]

C : increasing Hb affinity for O 2

D : increasing [H + ] and decreasing Hb affinity for O 2

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