BACE Chromatography Techniques 3

Question 1

What is a chromatogram?

Accepted Answer

A plot of detector signal versus elution volume or time

Answer

A chromatogram is a graphical output showing detector signal (e.g., UV absorbance) on the Y-axis versus elution volume or time on the X-axis, with peaks representing separated components.

Question 2

Which of the following best describes 'gradient elution' in ion exchange chromatography?

Accepted Answer

Progressively increasing salt concentration in the elution buffer

Answer

Gradient elution involves gradually increasing the salt concentration (or changing pH) to sequentially release proteins with different affinities for the resin.

Question 3

What is the function of a guard column in HPLC?

Accepted Answer

To protect the analytical column from particulates and contaminants

Answer

A guard column is a short, inexpensive column placed before the analytical column to trap particulates and strongly retained contaminants, extending analytical column life.

Question 4

In thin layer chromatography (TLC), the Rf value is calculated as:

Accepted Answer

Distance traveled by spot / distance traveled by solvent

Answer

Rf (retention factor) = distance traveled by the analyte spot ÷ distance traveled by the solvent front, and ranges from 0 to 1.

Question 5

When performing protein purification by chromatography, SDS-PAGE is typically run on collected fractions in order to:

Accepted Answer

Confirm the presence and purity of the target protein

Answer

SDS-PAGE separates proteins by size and visualizes bands, allowing the technician to confirm whether the target protein is present and to assess purity.

BACE - Biotechnician Assistant Credentialing Exam Practice Test

BACE - Biotechnician Assistant Credentialing Exam Practice Test

BACE Chromatography Techniques 3