Question

Agar-agar is commercially obtained from
A. Green algae
B. Blue-green algae
C. Brown algae
D. Red algae

Answer 1

Hint: Agar-agar is defined as a jelly-like material, which is received from the polysaccharide agarose. Agar is generally the subsequent assortment of two components - agarose, the straight polysaccharide and agaropectin, a heterogeneous mixture of modest atoms.

Complete answer:
The polysaccharide forms a supporting pattern in the cell walls of specific species of algae, but it is eliminated upon boiling. These algae are named as agarophytes and belong to the phylum Rhodophyta (red algae).
From the beginning of time unto current happenings, agar has been generally utilized as a fixing in sweets throughout Asia and as a strong substrate to contain culture media for microbiological works. It can be utilized as a diuretic, craving suppressant, vegan alternative for gelatine, thickener for soups, in jam preservatives, frozen yoghurt and different pastries and as an explaining operator in fermenting and for estimating paper and textures. The operator for gelling in agar is an unbranched polysaccharide which is collected from the cell walls of certain types of red algae growths, basically from the Gelidium and Gracilaria genera. In terms of chemistry, agar is characterized as a polymer that comprises subunits of the sugar, galactose. Agar-agar is collected from Rhodophyceae.

So, the correct answer is Option D i.e. Red algae.

Note: Green algae is also known as Chlorophyceae because of the presence of the green colour pigment, chlorophyll. Blue-green algae is known as cyanobacteria due to the presence of phycobilin and chlorophyll pigments. Brown algae is known as Phaeophyceae because of the presence of fucoxanthin, greenish brown colour pigment.