Q. Which of the following is one of the commercial products obtained from Gelidium and Gracilaria and are used to grow microbes and in preparations of ice-creams and jellies?
Answer: Agar
Notes: Agar, one of the commercial products obtained from Gelidium and Gracilaria are used to grow microbes and in preparations of ice-creams and jellies. The gelling agent in agar is an unbranched polysaccharide obtained from the cell walls of Gelidium and Gracilaria. For commercial purposes, it is derived primarily from Gelidium amansii. In chemical terms, agar is a polymer made up of subunits of the sugar galactose.