Electrophoresis Techniques and Protein Properties

The video tutorial explains protein electrophoresis, a technique used to separate proteins based on their size and charge. It covers the principles of electrophoretic mobility, the impact of pH and isoelectric points on protein charge, and various electrophoresis techniques like SDS PAGE and IEF. The tutorial also details the SDS PAGE process, including gel preparation and protein visualization methods such as staining and western blotting.

What property of proteins is inversely proportional to their electrophoretic mobility when they have the same charge?

• Net charge

• Molecular size

• Environmental pH

• Isoelectric point

How does an increase in environmental pH affect the net charge of proteins?

• Proteins carry a positive charge

• Proteins carry a negative charge

• Proteins do not change charge

• Proteins become neutral

What is the isoelectric point (pI) of a protein?

• The pH at which a protein carries a net negative charge

• The pH at which a protein carries a net positive charge

• The pH at which a protein carries zero net charge

• The pH at which a protein is most stable

Which electrophoresis technique separates proteins based on their pI?

• Capillary electrophoresis

• Native PAGE

• Isoelectric focusing

• SDS-PAGE

In SDS-PAGE, what is the role of the anionic detergent SDS?

• To disrupt protein tertiary structure and give a uniform negative charge

• To separate proteins by their pI

• To give proteins a uniform positive charge

• To maintain protein tertiary structure

What determines the pore size within the gel in SDS-PAGE?

• The concentration of the acrylamide gel

• The pH of the buffer

• The temperature of the gel

• The voltage applied

What is the purpose of the stacking effect in SDS-PAGE?

• To separate proteins by their pI

• To visualize proteins after electrophoresis

• To increase the speed of protein migration

• To ensure proteins reach the same starting point before separation

How does glycine behave in the electrode buffer during SDS-PAGE?

• It carries a positive charge

• It carries a negative charge

• It carries no charge

• It becomes a free radical

Which method is used to visualize proteins after electrophoresis?

• Isoelectric focusing

• Native PAGE

• Capillary electrophoresis

• Coomassie blue staining

What is the relationship between molecular weight and relative mobility of proteins?

• Directly proportional

• Inversely proportional

• No relationship

• Depends on the pH