Practice question

Blotting techniques are classified by target macromolecule: Southern blotting for DNA fragments, Northern for RNA transcripts, and Western for proteins, also called immunoblotting. Western blotting involves electrophoretic transfer of resolved proteins from polyacrylamide gel onto nitrocellulose or PVDF membrane, followed by blocking to prevent nonspecific binding and incubation with highly specific primary antibodies and enzyme-linked secondary antibodies for chemiluminescent or colorimetric detection. This identifies molecular weight, abundance and modifications of specific proteins. Lipids, DNA and sugars require thin-layer chromatography, Southern blotting or periodic acid-Schiff staining, not immunoblotting.