$$ \theta = \frac{[L]^n}{K_d + [L]^n} $$

Question 1

Which model best explains the cooperative binding of oxygen to hemoglobin?

Accepted Answer

Concerted (MWC) model

Question 2

In the context of allosteric enzymes, what does the 'T state' refer to?

Accepted Answer

The tense state with lower substrate affinity

Question 3

Which of the following statements about the R state in the concerted model is correct?

Accepted Answer

It has a higher affinity for substrate than the T state.

Question 4

What is the effect of an allosteric activator on the equilibrium between the T and R states?

Accepted Answer

It shifts the equilibrium toward the R state.

Question 5

Which of the following best describes the term 'cooperativity' in enzyme kinetics?

Accepted Answer

The binding of one substrate molecule increases the affinity for subsequent substrate molecules.

Question 6

If an allosteric inhibitor is added to an enzyme following the concerted model, what is the expected effect on the fraction of enzyme in the R state?

Accepted Answer

The fraction of enzyme in the R state decreases.

Question 7

Which equation best represents the Hill equation for cooperative binding?

Accepted Answer

$$ 	heta = \frac{[L]^n}{K_d + [L]^n} $$

Question 8

A sigmoidal substrate-velocity curve is characteristic of which type of enzyme behavior?

Accepted Answer

Cooperative binding

Question 9

Which of the following would most likely increase the Hill coefficient ($$n) $$for an allosteric enzyme?

Accepted Answer

Increased cooperativity among subunits

Question 10

In a clinical scenario, a patient has a mutation that stabilizes the T state of hemoglobin. What is the most likely physiological consequence?

Accepted Answer

Reduced oxygen delivery to tissues

Question 11

Which of the following statements about the concerted (MWC) model is FALSE?

Accepted Answer

Subunits can exist in both T and R states simultaneously within the same enzyme molecule.

Question 12

Which of the following is a real-life example of an allosteric enzyme regulated by the concerted model?

Accepted Answer

Aspartate transcarbamoylase (ATCase)

Question 13

If the fraction of enzyme in the R state is increased, what happens to the enzyme's affinity for substrate?

Accepted Answer

Affinity for substrate increases.

Question 14

Which of the following best describes the effect of a positive allosteric effector?

Accepted Answer

It increases the proportion of enzyme in the R state.

Question 15

A mutation causes an allosteric enzyme to lose its cooperative behavior. Which kinetic curve would you expect to see?

Accepted Answer

A hyperbolic curve similar to Michaelis-Menten kinetics

Question 16

Which of the following is NOT a characteristic of allosteric enzymes?

Accepted Answer

They follow simple Michaelis-Menten kinetics.

Question 17

Which of the following equations describes the equilibrium between the T and R states in the concerted model?

Accepted Answer

$$ L = \frac{[T_0$]}{[R_0$]} $$

Question 18

Which of the following would decrease the fraction of enzyme in the R state according to the concerted model?

Accepted Answer

Addition of an allosteric inhibitor

Question 19

In the context of the concerted model, what is the primary effect of a negative allosteric effector?

Accepted Answer

It stabilizes the T state.

Question 20

Which of the following best explains why hemoglobin is more efficient at oxygen delivery than myoglobin?

Accepted Answer

Hemoglobin exhibits cooperative binding, allowing for efficient oxygen loading and unloading.

Concerted Model of Allosteric Regulation and Hemoglobin Function

Guida di studio - Domande di pratica