Separating charged biomolecules — name the technique Charged molecules (DNA, RNA, proteins) can be separated based on different migration rates through a hydrated solid matrix when subjected to an electric field. What is this analytical technique called?

Introduction / Context:Laboratories routinely separate nucleic acids and proteins to assess size, purity, and identity. A key method exploits charge-based migration through a porous gel under an electric field. Recognizing the correct term helps distinguish it from related but distinct techniques such as blotting and autoradiography, which are downstream detection steps.

Given Data / Assumptions:

• Molecules carry net charge depending on pH and composition.
• Porous matrices (agarose for nucleic acids, polyacrylamide for proteins) impede larger molecules.
• An applied electric field drives migration toward the oppositely charged electrode.

Concept / Approach:

Gel electrophoresis separates by size and charge: DNA/RNA mainly by size (uniform charge density), proteins by size and charge (native PAGE) or by size alone when denatured with SDS (SDS-PAGE). Autoradiography visualizes radio-labeled molecules after separation; blotting transfers separated molecules to membranes for probing; photoreactivation is a DNA repair process, not a separation technique.

Step-by-Step Solution:

Verification / Alternative check:

Resolution and band patterns correlate with known ladders and molecular weights/lengths, confirming proper electrophoretic separation.

Why Other Options Are Wrong:

Photoreactivation is enzymatic repair; autoradiography detects radioactivity; blotting is transfer, not separation; isoelectric focusing is a form of electrophoresis but typically performed in gels or strips and not the general name requested.

Common Pitfalls:

Confusing detection or transfer methods with the core separation step.

Final Answer:

Gel electrophoresis