Visualizing proteins in polyacrylamide gels — Which approach directly reveals protein bands after electrophoresis?

Introduction:
After electrophoresis, proteins in polyacrylamide gels are typically invisible. Visualization requires dyes or labels that bind proteins to produce contrast against the clear gel background.

Given Data / Assumptions:

• Most proteins lack intrinsic color at low concentrations.
• Common dyes include Coomassie Brilliant Blue and silver stain; fluorescent stains are also used.
• Gels must often be destained to reduce background.

Concept / Approach:
Dyes interact non-covalently with proteins, allowing discrete bands to be seen and documented. Sensitivity and linearity vary by stain, influencing quantitation and detection limits.

Step-by-Step Solution:

Verification / Alternative check:
Include molecular weight standards; their visible bands confirm staining quality and enable mass estimation by comparison.

Why Other Options Are Wrong:

Common Pitfalls:
Overstaining leading to high background; under-destaining obscuring bands; neglecting fixation steps when required by the staining protocol.

Final Answer:
Stain the gel with a protein-binding dye to visualize bands.