Agarose is a neutral linear polysaccharide extracted from marine red algae, consisting of repeating agarobiose units of β-D-galactopyranose and 3,6-anhydro-α-L-galactopyranose linked by alternating β-1,3 and α-1,4 glycosidic bonds. It forms thermoreversible gels widely used in molecular biology for agarose gel electrophoresis to separate nucleic acids and proteins based on size. The gel matrix provides a porous network whose pore size depends on concentration, typically 0.5-2%. Agarose is insoluble in cold water but dissolves in boiling water to form clear solutions that gel upon cooling below 40°C. It is chemically inert, highly purified for low electroendosmosis, and valued for its high gel strength and clarity. Applications extend to chromatography, tissue engineering scaffolds, and food stabilizers.