Question

Spirogyra is commonly called pond silk because A. Silk is manufactured from it. B. It looks like silk thread C. Filament shine like silk due to the presence of mucilage D. None of the above

Answer 1

Hint: Spirogyra is one of the long filamentous, unbranched and special types of algae which is commonly known as mermaid’s tresses or water silk.

Complete answer:
Algae are known as thallophytes which are mainly unicellular or multicellular structures are bearing chlorophyll. They are autotrophic and largely aquatic. They are found in soils and woods. Algae are classified as Chlorophyta, Phaeophyta and Rhodophyta. Chlorophyta are the class of algae which contains chlorophyll a and b, they are freshwater habitat may be unicellular or multicellular. Other examples of Chlorophyta are Chlorella, Ultrix, Volvo, and Chlamydomonas.

Spirogyra belongs to a class of algae called Chlorophytes. They are unbranched, filamentous, free floating algae of stagnant freshwater. Cells are interconnected with each other and are cylindrical in shape. It shows a presence of mucilage sheath on the outer side. The cell wall is made up of two layers outer of pectin and inner of cellulose. The outer part dissolves in the water to form a mucilaginous sheath. It gives a slimy touch to the Spirogyra. They reproduce through vegetative, asexual and sexual reproduction. The filaments found in the Spirogyra are in the length mainly in centimetre.

Hence, the correct answer is option (C).

Note: Pectin is a naturally occurring heteropolysaccharide. Phaeophyta shows the presence of chlorophyll a, c ,and fucoxanthin and are known as brown algae. Red algae have red pigment called Phycoerythrin.