Question

Mannitol is the stored food in
A.Gracilaria
B.Chara
C.Porphyra
D.Fucus

Answer 1

Mannitol is an organic compound which is derived from sugar, containing one hydroxyl group which is attached to each carbon atom. It is stored as food in food in the body of algae and catabolized when energy is required.

Complete answer: Food materials such as oils, starch, Floridean starch, and laminarin are stored in the body of algae and used whenever required. Gracilaria is a type of red algae and is known for its economic importance. Floridean starch is stored as food in Gracilaria. Therefore, option A is wrong. Chara is a multicellular green alga found in freshwater and grows submerged attached to the bottom. Food stored in them is in the form of starch and oil. Hence, option B is wrong. Porphyra is a type of red algae that belongs to the variety of cold-water seaweed algae. The food material stored in Porphyra is in the form of foridean starch. Therefore, option C is also incorrect. Fucus is a brown alga that is found in the rocky seashores. The food stored in Fucus is in the form of oil, mannitol, and laminarin.
So, option D is the correct answer.

Additional information:
Sugar alcohols are organic compounds that are derived from sugar-containing one hydroxyl group which is attached to each carbon atom. One of the types of sugar alcohol is mannitol which is used as a sweetener and for medication.

Note: Mannitol is used as an artificial sweetener for diabetic patients as it is poorly absorbed by the intestine. For patients suffering from glaucoma, mannitol is used as a medication to decrease the pressure in the eyes. Electrolyte problems and dehydration are the common side effects of using mannitol. It is also used as a laxative.