Which substance is used in gel electrophoresis and is derived from seaweed?

• A. Agarose
• B. Agar
• C. Starch
• D. Cellulose

Answer: (A)

Gel electrophoresis needs a gel matrix that is porous and inert, so DNA fragments can separate by size as they migrate through the gel. Agarose fits this role because it forms a uniform, stable gel when melted and cooled, providing consistent pore sizes that let smaller DNA fragments move faster than larger ones. Agarose is derived from seaweed, specifically red algae, and is the purified component of agar used for precise DNA separation. In contrast, agar contains additional components that can affect pore uniformity, starch gels have poorer resolution for DNA, and cellulose does not form suitable gels for electrophoresis. So the seaweed-derived substance used in gel electrophoresis is agarose.