Question 1

Affinity chromatography separates proteins based on which property?

Accepted Answer

Their affinity for a specific ligand

Question 2

In affinity chromatography, what is the role of the stationary phase?

Accepted Answer

It contains a ligand that specifically binds the target protein

Question 3

A protein is eluted from an affinity column by adding a solution containing:

Accepted Answer

A free ligand that competes for binding

Question 4

Which of the following best describes the process of eluting a bound protein from an affinity column?

Accepted Answer

Adding a solution with a high concentration of the ligand to the mobile phase

Question 5

A researcher wants to purify a DNA-binding protein using affinity chromatography. Which ligand should be attached to the stationary phase?

Accepted Answer

DNA or a DNA analog

Question 6

Which of the following is a disadvantage of affinity chromatography?

Accepted Answer

Non-specific binding can reduce purity

Question 7

If a protein does not bind to the ligand in the affinity column, what will happen?

Accepted Answer

It will pass through the column in the flow-through

Question 8

Which equation best represents the binding equilibrium in affinity chromatography?

Accepted Answer

$$P + L \rightleftharpoons PL$$

Question 9

A protein with a major DNA-binding motif is best separated from other proteins using which technique?

Accepted Answer

Affinity chromatography with DNA as the ligand

Question 10

Which of the following would most likely increase the yield of a target protein in affinity chromatography?

Accepted Answer

Increasing the amount of ligand attached to the stationary phase

Question 11

A scientist is purifying a protein that binds ATP. Which stationary phase modification would be most effective?

Accepted Answer

Attaching ATP or an ATP analog to the stationary phase

Question 12

Which step in affinity chromatography is most critical for ensuring specificity of protein purification?

Accepted Answer

Choosing a ligand that binds only the target protein

Question 13

If a protein is eluted from an affinity column by raising the temperature, what is the most likely effect?

Accepted Answer

The protein-ligand interaction is disrupted, releasing the protein

Question 14

Which of the following is NOT a typical method for eluting a protein from an affinity column?

Accepted Answer

Adding a reducing agent

Question 15

A protein with a major DNA-binding motif and a molecular weight of 22,000 Da is best separated from a protein with no DNA-binding motif using:

Accepted Answer

Affinity chromatography with DNA as the ligand

Question 16

Which of the following would decrease the specificity of affinity chromatography?

Accepted Answer

Using a ligand that binds multiple proteins

Question 17

In a multi-step purification, why might affinity chromatography be used as the final step?

Accepted Answer

It provides high specificity and purity for the target protein

Question 18

Which of the following is a real-world application of affinity chromatography?

Accepted Answer

Purification of monoclonal antibodies using Protein A columns

Question 19

A protein is purified using affinity chromatography, but the yield is low. Which troubleshooting step is most appropriate?

Accepted Answer

Check if the ligand is still active and properly attached to the stationary phase

Question 20

Which of the following best explains why affinity chromatography can achieve high purity in a single step?

Accepted Answer

The target protein binds specifically to the ligand, while other proteins do not

Affinity Chromatography and Protein Purification Techniques

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