Title: Quiz: Chromatography
Course: BTEC-2020-301-302-303-F21 > Section: Chromatography

Q: Which protein will come off a size exclusion chromatography column first?
- A small protein
- A large protein
A: A large protein
If right: Correct. Because large proteins are excluded from the volume within the beads, they travel through the column more quickly than small proteins.
If wrong: Incorrect. Because large proteins are excluded from the volume within the beads, they travel through the column more quickly than small proteins.

Q: Which type of chromatography relies on beads that have a positive or negative charge?
- Affinity chromatography
- Ion exchange chromatography
- Size exclusion chromatography
A: Ion exchange chromatography
If right: Correct! Ion exchange chromatography uses charged beads in the column.
If wrong: Incorrect. Review the hand-drawn intro to chromatography video.

Q: Which type of chromatography may use beads that have antibodies bound to them?
- Affinity chromatography
- Ion exchange chromatography
- Size exclusion chromatography
A: Affinity chromatography
If right: Correct! One type of affinity chromatography uses antibodies bound to the beads.
If wrong: Incorrect. Review the text descriptions of the three types of chromatography.

Q: Which type of chromatography may use beads that have your POI's ligand attached to them?
- Affinity chromatography
- Ion exchange chromatography
- Size exclusion chromatography
A: Affinity chromatography
If right: Correct! One type of affinity chromatography uses the POI's ligand attached to beads.
If wrong: Incorrect. Review the text descriptions of the three types of chromatography.

Q: How does increasing the salt concentration cause elution in ion exchange chromatography?
- The salt denatures the proteins, causing them to elute.
- The ions in the salt bind to the beads, displacing the bound proteins.
- The salt plugs the pores in the beads so that the proteins can't get inside.
- The ions in the salt allow an enzyme to cut off the bound proteins.
A: The ions in the salt bind to the beads, displacing the bound proteins.
If right: Correct!
If wrong: Incorrect. Review the video on ion exchange chromatography.

Q: What is another name for the buffer that runs through a column during chromatography?
- Stationary phase
- Mobile phase
- Column phase
- Elution phase
A: Mobile phase
If right: Correct.
If wrong: Incorrect. Review the introductory text on chromatography.

Q: What is another name for the beads in a chromatography column?
- Stationary phase
- Mobile phase
- Column phase
- Elution phase
A: Stationary phase
If right: Correct.
If wrong: Incorrect. Review the introductory text on chromatography.

Q: Which type of chromatography does not require a buffer change for elution?
- Affinity chromatography
- Ion exchange chromatography
- Size exclusion chromatography
A: Size exclusion chromatography
If right: Correct! Size exclusion chromatography does not require a buffer change for elution.
If wrong: Incorrect. Review the hand-drawn intro to chromatography video.

Q: The image below shows a size exclusion elution profile with the peaks labeled. Which peak contains the biggest proteins?
- A
- B
- C
A: A
If right: Correct! Big proteins move quickly through a size exclusion column because they are excluded from the volume within the pores.
If wrong: Incorrect. Review the video on size exclusion chromatography.

Q: The image below shows an ion exchange profile with the peaks labeled. The column contains beads that are positively charged. Which peak represents positively charged proteins?
- A
- B
- C
- D
- E
- F
A: A
If right: Correct! Positively charged proteins won't bind to positively charged beads, so they will flow through during sample application.
If wrong: Incorrect. Review the video on ion exchange chromatography.

Q: The image below shows an ion exchange profile with the peaks labeled. The column contains beads that are positively charged. Which peak represents the high-salt buffer used for regeneration of the column?
- A
- B
- C
- D
- E
- F
A: E
If right: Correct! The blue line on this graph represents the ionic strength of the buffer.
If wrong: Incorrect. Review the video on ion exchange chromatography.

Q: The image below shows an ion exchange profile with the peaks labeled. The column contains beads that are positively charged. Which peak represents the purified protein with the most negative charges?
- A
- B
- C
- D
- E
- F
A: D
If right: Correct! D represents the most negatively charged protein purified in this experiment. The more negatively charged the protein on this column, the longer it will stick. Note that peak F only occurs during the regeneration phase and is shorter and wider, meaning it probably contains a variety of really strongly negatively charged molecules ("junk" in this experiment), rather than the purified proteins (B, C, and D) that elute during the elution phase.
If wrong: Incorrect. Review the video on ion exchange chromatography.

Q: The image below shows an affinity chromatography profile with the peaks labeled. The column contains beads with lactose attached. Which peak represents where phosphatase would elute from this column? (Lactose is not a ligand for phosphatase.)
- A
- B
- C
A: A
If right: Correct! Because phosphatase does not bind to lactose, it won't stick to the beads, and will flow through the column upon sample application.
If wrong: Incorrect. Review the hand-drawn intro to chromatography video.

Q: The image below shows an affinity chromatography profile with the peaks labeled. This time, the beads in the column have nickel ions bound to them, and we are purifying a his-tagged protein. What does the red line that makes peak C represent?
- The concentration of imidazole.
- The concentration of salt.
- The pH.
- The elution of the POI.
A: The concentration of imidazole.
If right: Correct! Imidazole elutes his-tagged proteins off a nickel column. You'll do this with BglA in the final project for this course.
If wrong: Incorrect. Review the text describing affinity chromatography.