What is the structure of Spirogyra as per NCERT?

Spirogyra is a filamentous green alga found in freshwater environments. According to the NCERT syllabus, its structure can be described as follows:

• Spirogyra consists of unbranched, free-floating filaments.
• Each filament is composed of cylindrical cells connected end to end.
• The most notable feature of Spirogyra is the presence of spiral chloroplasts in each cell, which is the reason behind its name.
• The cells have a clear, mucilaginous sheath surrounding them.
• Each cell also contains a nucleus, pyrenoids (for starch storage), and a central vacuole.

Here is a simple diagram of Spirogyra:

In this diagram, you can see the spiral chloroplasts and the cellular structure clearly.