What is agar agar?

A study tour of secondary class students team visited a tissue culture laboratory noticed a chemical labelled as " agar-agar" is adding to the culture medium. The same team visited an icecream factory happened to see the same material adding in the icecream mix. They asked the following questions to the teacher. (a) what is agar- agar? (b) Is it poisonous (c) What is the common purpose to using this? (d) How are they synthesized? Imagine that you are the teacher who is facing these queastions. Clarify the doubts of the students.

What is an agar?

What are the sources in algae for alginate, agar agar and carrageenan?

Polysaccharide agar-agar is obtained from

What is Agar? Mention its role in plant tissue culture.

From which agar-agar is obtained?

Assumption: Agar-agar is a carbohydrate obtained from some sea weeds. Reason: Agar agar is a polysaccharides formed of many galactose monomers.

Saturated solution of KNO_3 with agar-agar is used to make 'salt bridge' because: