Which electrophoresis method yields discrete bands rather than a continuous gradient?

Which electrophoresis method yields discrete bands rather than a continuous gradient?

• A. Zone electrophoresis
• B. Isoelectric focusing
• C. Immunoelectrophoresis
• D. Nonelectrophoresis

Answer: (A)

Zone electrophoresis gives you a uniform environment in the gel and the electric field, so each component in the sample moves at its own characteristic speed. Because the sample is loaded as a narrow zone and diffusion is limited, the separated components form distinct, well-defined regions that show up as discrete bands. The pattern is a set of separated bands rather than a continuous spread. In other methods, the separation environment or the chemistry creates different kinds of patterns. For example, a pH gradient in methods like isoelectric focusing is continuous along the gel, so the separation happens at specific points along that gradient, which is a different visual pattern. Immunoelectrophoresis relies on antigen–antibody reactions and typically shows lines or arcs rather than clean bands, and nonelectrophoresis isn’t an electrophoretic technique at all.

Zone electrophoresis gives you a uniform environment in the gel and the electric field, so each component in the sample moves at its own characteristic speed. Because the sample is loaded as a narrow zone and diffusion is limited, the separated components form distinct, well-defined regions that show up as discrete bands. The pattern is a set of separated bands rather than a continuous spread.

In other methods, the separation environment or the chemistry creates different kinds of patterns. For example, a pH gradient in methods like isoelectric focusing is continuous along the gel, so the separation happens at specific points along that gradient, which is a different visual pattern. Immunoelectrophoresis relies on antigen–antibody reactions and typically shows lines or arcs rather than clean bands, and nonelectrophoresis isn’t an electrophoretic technique at all.