What does agarose mean?
Agarose is a naturally occurring polysaccharide — a long chain of sugar units — that is extracted and purified from agar, the gelling substance derived from certain red seaweeds. In everyday life it has little presence, but in the laboratory it is indispensable: because it forms a porous gel when dissolved in water and cooled, agarose serves as the standard medium for gel electrophoresis, the technique by which scientists separate DNA, RNA, and other large molecules according to their size. By adjusting the concentration of agarose, researchers control the pore size of the gel and thus how finely they can resolve molecular fragments of different lengths. The word belongs firmly to technical vocabulary, appearing in molecular biology papers, protocols, and classroom exercises rather than general conversation. Its name reflects its chemical identity, combining 'agar' with '-ose', the suffix conventionally attached to sugars and carbohydrates.
nounA gelatinous polysaccharide obtained from agar and used chiefly as a medium for separating molecules such as DNA fragments by gel electrophoresis.
- A neutral gelling polysaccharide extracted from agar, used as a matrix for gel electrophoresis and other laboratory separations.
"The DNA fragments were separated according to size on a one percent agarose gel."
"The researchers ran the PCR products through an agarose gel to confirm the fragment sizes."
"Higher concentrations of agarose produce smaller pores, allowing finer resolution of short DNA fragments."
As a substance, agarose is not counted; amounts are given by weight or concentration instead.
"Weigh out three grams of agarose before dissolving it in buffer."
Every time scientists read a DNA sequence, chances are that DNA took a journey through a jelly made of agarose — a purified slice of seaweed chemistry.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of agarose
The word agarose was coined in the twentieth century from 'agar', itself borrowed into English from Malay 'agar-agar', the name of the gelatinous substance extracted from red seaweed, combined with '-ose', the standard chemical suffix for sugars and carbohydrates. It therefore shares its '-ose' ending with familiar carbohydrate names such as glucose, sucrose, and lactose, though those substances are unrelated in origin. Agarose came into widespread use alongside the rise of gel electrophoresis in the mid-twentieth century.
How agarose is actually used
Agarose is a technical term confined almost entirely to scientific contexts, particularly molecular biology and biochemistry. It is always written as a single unhyphenated word and is treated as an uncountable mass noun when referring to the substance itself.
Easily confused with agarose
Agar is the broader gelling substance extracted from seaweed, while agarose is one specific purified component of agar used mainly in laboratory electrophoresis.