Which method is commonly used to separate proteins based on their size?

• Western blotting

• Gel electrophoresis

• Reverse -Phase HPLC

• Mass spectrometry

What is the role of a buffer in electrophoresis?

• To maintain acidity during electrophoresis.

• To provide a source of energy for the reaction.

• To maintain stable pH and ionic strength.

• To act as a dye for visualizing the samples.

Which of the following is NOT a step in protein purification?

• Chromatography

• Fermentation

• Electrophoresis

• Centrifugation

True or False: Electrophoresis can only be performed on DNA samples.

• False: Electrophoresis can only be used for RNA samples

• True

• False: Electrophoresis is only for proteins

• False: Electrophoresis can be used for proteins and DNA samples

Describe the principle behind centrifugation.

• Centrifugation separates components of a mixture based on density using centrifugal force.

• Centrifugation uses magnetic fields to isolate substances.

• Centrifugation relies on temperature to separate components.

• Centrifugation mixes components of a mixture evenly.

What is the significance of the isoelectric point in protein purification?

• The isoelectric point indicates the optimal pH for protein activity.

• The isoelectric point determines the molecular weight of proteins.

• The isoelectric point is used to measure protein solubility in water.

• The isoelectric point allows for the selective precipitation and separation of proteins based on their charge.

Which type of gel is commonly used in SDS-PAGE?

• Polyethylene glycol

• Starch

• Polyacrylamide

• Agarose

True or False: The higher the molecular weight of a protein, the faster it migrates in an electric field.

• True

• False: Molecular weight has no effect on migration speed.

• False: The higher the molecular weight of a protein, the slower it migrates in an electric field.

Explain how affinity chromatography works in protein purification.

• Affinity chromatography relies on electrical charges to purify proteins.

• Affinity chromatography purifies proteins based on their specific binding interactions with buffers

• Affinity chromatography purifies proteins based on their specific binding interactions with ligands.

• Affinity chromatography separates proteins based on their size.

What is the main driving force for protein migration in electrophoresis?

• Electric field

• Centrifugal force

• Gravity

• Temperature