Electrophoresis Quiz

Native PAGE separates proteins based only on their molecular weight.

• True

• False

Answer explanation

Native PAGE separates proteins based on their charge-to-mass ratio, not just molecular weight, preserving their native structure and biological activity.

SDS-PAGE requires the use of SDS and a reducing agent like β-mercaptoethanol for protein denaturation.

• True

• False

In SDS-PAGE, proteins are separated based on their intrinsic charge.

• True

• False

Answer explanation

SDS imparts a uniform negative charge to proteins, so separation in SDS-PAGE is based on molecular weight alone.

The resolving power of SDS-PAGE depends on the concentration of acrylamide in the gel.

• True

• False

Isoelectric focusing (IEF) separates proteins based on their isoelectric points (pI).

• True

• False

In IEF, proteins migrate until they reach a pH region where their net charge is zero.

• True

• False

Coomassie blue staining is more sensitive than silver staining.

• True

• False

Answer explanation

Silver staining is more sensitive than Coomassie blue, detecting protein levels as low as 0.2–1.5 ng compared to 3–50 ng for Coomassie blue.

Silver staining is a fluorescent detection method.

• True

• False

In 2D electrophoresis, the first dimension separates proteins based on molecular weight.

• True

• False

Answer explanation

The first dimension in 2D electrophoresis separates proteins based on their pI (isoelectric focusing).

2D electrophoresis combines isoelectric focusing and SDS-PAGE.

• True

• False