Allosteric Effects

Question: A protein that shows infinite cooperative for binding of n ligands will
[A].

show a Hill coefficient (nH) of 0.0

[B].

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

[C].

show a Hill coefficient (nH) of n

[D].

both (b) and (c)

Answer: Option D

Explanation:

No answer description available for this question.

Question: The Hill coefficient (nH) for myoglobin and hemoglobin are respectively
[A].

2.8 and 1.0

[B].

1.0 and 2.8

[C].

1.2 and 4.5

[D].

4.5 and 1.2

Answer: Option B

Explanation:

No answer description available for this question.

Question: When protein binds two ligands in a non-cooperative manner, then the x-intercept of the Scatchard Plot is
[A].

1

[B].

2

[C].

not defined

[D].

none of the above

Answer: Option B

Explanation:

No answer description available for this question.

Question: A protein that binds two ligands in a non-cooperative manner will show
[A].

a sigmodial binding curve

[B].

a hyperbolic binding curve

[C].

a linear Scatchard Plot

[D].

both (b) and (c)

Answer: Option D

Explanation:

No answer description available for this question.

Question: The specificity of a ligand binding site on a protein is based on
[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

Answer: Option B

Explanation:

No answer description available for this question.

Question: The conformational changes from the T to the R state is initiated by
[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

Answer: Option A

Explanation:

No answer description available for this question.

Question: Bisphosphoglycerate (BPG) cannot bind to the oxygenated R state of hemoglobin because
[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

Answer: Option C

Explanation:

No answer description available for this question.

Question: An allosteric activator
[A].

increases the binding affinity

[B].

decreases the binding affinity

[C].

stabilizes the R state of the protein

[D].

both (a) and (c)

Answer: Option D

Explanation:

No answer description available for this question.

Question: Small molecules affect hemoglobin (Hb) by
[A].

decreasing Hb affinity for O2

[B].

increasing [H+]

[C].

increasing Hb affinity for O2

[D].

increasing [H+] and decreasing Hb affinity for O2

Answer: Option D

Explanation:

No answer description available for this question.

Question: O2 binding to hemoglobin results in
[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

Answer: Option C

Explanation:

No answer description available for this question.