Virtual Labs

Thermodynamic characterization of protein-ligand binding by isothermal titration calorimetry (ITC)

1. Which of the following is a common application of ITC?

a: Protein expression Explanation

Explanation

b: Ligand screening Explanation

Explanation

c: DNA sequencing Explanation

Explanation

d: Cell culture optimisation Explanation

Explanation

2. What is the primary advantage of ITC over other binding assays?

a: High-sensitivity Explanation

Explanation

b: Low cost Explanation

Explanation

c: Speed Explanation

Explanation

d: Ease of use Explanation

Explanation

3. What information does the shape of the ITC curve provide?

a: Rate constant Explanation

Explanation

b: Thermodynamic parameters Explanation

Explanation

c: Reaction order Explanation

Explanation

d: Activation energy Explanation

Explanation

4. What is the role of the reference cell in an ITC experiment?

a: To measure the absolute temperature of the solution Explanation

Explanation

b: To calibrate the injection syringe for accurate volume delivery Explanation

Explanation

c: To provide a baseline for comparison with the heat changes in the sample cell Explanation

Explanation

d: To monitor changes in pressure during the titration process Explanation

Explanation

5. Which of the following statements regarding the interpretation of ITC data is correct?

a: A positive enthalpy change (ΔH) always indicates an exothermic reaction Explanation

Explanation

b: The shape of the ITC curve is independent of the stoichiometry of the binding interaction Explanation

Explanation

c: The binding constant (Ka) can be accurately determined from a single ITC experiment Explanation

Explanation

d: An isothermal experiment can accurately measure changes in entropy (ΔS) Explanation

Explanation

6. In an ITC experiment, what is the primary reason for injecting the titrant solution incrementally rather than all at once?

a: To reduce experimental time Explanation

Explanation

b: To avoid dilution effects Explanation

Explanation

c: To maintain a constant pH Explanation

Explanation

d: To minimize heat loss to the surroundings Explanation

Explanation

7. In an ITC experiment, what does the term 'stoichiometry' refer to?

a: The ratio of titrant to sample volume in each injection Explanation

Explanation

b: The ratio of the concentrations of the interacting molecules Explanation

Explanation

c: The number of binding sites on the sample molecule Explanation

Explanation

d: The number of injections required to achieve binding saturation Explanation

Explanation

8. Which of the following factors can affect the accuracy of the enthalpy change (ΔH) measured by ITC?

a: Temperature fluctuations during the experiment Explanation

Explanation

b: Size of the syringe used for injections Explanation

Explanation

c: Concentration of the titrant solution Explanation

Explanation

d: pH of the buffer solution Explanation

Explanation

9. Which of the following techniques is commonly used to validate the results obtained from an ITC experiment?

a: Dynamic light scattering (DLS) Explanation

Explanation

b: Surface plasmon resonance (SPR) Explanation

Explanation

c: Nuclear magnetic resonance (NMR) Explanation

Explanation

d: Differential scanning calorimetry (DSC) Explanation

Explanation

10. Which of the following factors should be considered when selecting the appropriate buffer for an ITC experiment?

a: Buffer pKa Explanation

Explanation

b: Buffer viscosity Explanation

Explanation

c: Buffer refractive index Explanation

Explanation

d: Buffer concentration Explanation

Explanation