Question 1

Which of the following is the primary reason for determining the purity of a protein during a purification workflow?

Accepted Answer

To confirm the protein is free from unwanted contaminants

Question 2

During the initial planning of a protein purification workflow, which factor is LEAST likely to influence the choice of purification strategy?

Accepted Answer

The color of the protein solution

Question 3

Which technique is commonly used to analyze the purity of a protein sample?

Accepted Answer

SDS-PAGE

Question 4

A researcher needs to remove insoluble debris from a protein extract. Which method should they use?

Accepted Answer

Centrifugation

Question 5

Which equation best represents the calculation of protein concentration using absorbance at 280 nm?

Accepted Answer

$C = \frac{A_{280}}{\varepsilon \cdot l}$

Question 6

Which of the following is a critical consideration when scaling up protein purification from lab to production?

Accepted Answer

Process time and equipment availability

Question 7

A protein sample is purified using affinity chromatography. What property of the protein is exploited in this technique?

Accepted Answer

Specific binding to a ligand

Question 8

Which method is most appropriate for concentrating a protein solution before further purification steps?

Accepted Answer

Ultrafiltration

Question 9

In cell lysis/disintegration, which technique is NOT mechanical?

Accepted Answer

Chemical lysis

Question 10

Which of the following is a key advantage of using size-exclusion chromatography in protein purification?

Accepted Answer

It removes minor contaminants and provides high resolution

Question 11

A scientist needs to purify a protein that must remain functional for downstream applications. Which purification method should they prioritize?

Accepted Answer

Purification by exploitation of activity

Question 12

Which of the following is NOT a typical step in the clarification of a protein extract?

Accepted Answer

Affinity chromatography

Question 13

If a protein is unstable during purification, which factor is most likely to help maintain its stability?

Accepted Answer

Using appropriate buffers and reagents

Question 14

Which property is most important for separation in ion-exchange chromatography?

Accepted Answer

Protein charge

Question 15

A protein purification protocol includes the following steps: cell lysis, centrifugation, ultrafiltration, and affinity chromatography. What is the main purpose of ultrafiltration in this workflow?

Accepted Answer

To concentrate the protein solution

Question 16

Which of the following equations correctly describes the relationship between sample volume ($V$), protein concentration ($C$), and total protein amount ($P$)?

Accepted Answer

$P = V \cdot C$

Question 17

Which step in protein purification is most likely to be affected by mass transfer limitations during scale-up?

Accepted Answer

Chromatography

Question 18

A protein sample is analyzed by SDS-PAGE and shows multiple bands. What does this indicate?

Accepted Answer

The sample contains multiple proteins or contaminants

Question 19

Which of the following is a common misconception about protein purification scale-up?

Accepted Answer

Scale-up does not affect protein yield

Question 20

A researcher is using gel filtration chromatography to purify a protein. What is the main principle behind this technique?

Accepted Answer

Separation based on protein size

Protein Purification: Strategies, Techniques, and Scale-Up in Biochemistry

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