An extract of certain species of red seaweeds that is used as a gelling agent in microbiological culture media, foodstuffs, medicines, and cosmetic creams and jellies. Nutrient agar consists of a broth made from beef extract or blood that is gelled with agar and used for the cultivation of bacteria, fungi, and some algae. Agarose is a polysaccharide component of agar that in purified form is widely used to form a gel-like matrix in electrophoresis and chromatography. It consists of alternating units of d-galactose and anhydrogalactose.