Question

Nitrogen fixing heterocyst is a characteristic feature of

A) Chrysophytes
B) Mycoplasma
C) Protozoans
D) Anabaena ​

Answer 1

Answer: Anabaena

Explanation: Heterocyst-forming cyanobacteria differentiate highly specialized cells to provide fixed nitrogen to the vegetative cells in a filament. Anabaena is a genus of filamentous cyanobacteria that exist as plankton. They are known for nitrogen-fixing abilities and for their symbiotic relationships.

Answer 2

Answer:

Nitrogen fixing heterocyst is a characteristic feature of Anabaena.

Explanation:

• Some filamentous cyanobacteria, including Nostoc punctiforme, Cylindrospermum stagnale, and Anabaena sphaerica, produce specialised nitrogen-fixing cells known as heterocysts or heterocytes during nitrogen shortage.
• Using the enzyme nitrogenase, they fix nitrogen from dinitrogen (N2) in the air to provide the filament's cells the nitrogen they need for biosynthesis.
• Anabaena cyanobacteria and Azolla plants have a notable symbiotic interaction.
• Anabaena are found inside and on the stems of Azolla plants. The Anabaena uses fixed carbon from the Azolla plant's photosynthesis as an energy source for di nitrogenases in the heterocyst cells.
• In exchange, the heterocysts can deliver fixed nitrogen in the form of ammonia to the vegetative cells and the Azolla plant, supporting the growth of both species.

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