Biological Classification And System Of Classification Question 23
Question: In Nostoc the heterocysts are
Options:
A) Terminal
B) Intercalary
C) Both (a) and (b)
D) None of these
Show Answer
Answer:
Correct Answer: B
Solution:
Nostoc is a genus of blue-green algae or cyanobacteria. They are prokaryotic and perform photosynthesis.
Heterocysts are specialized nitrogen-fixing cells formed during nitrogen starvation by some filamentous cyanobacteria, such as Nostoc.
They fix nitrogen from dinitrogen ($N_2$) in the air using the enzyme nitrogenase, in order to provide the cells in the filament with nitrogen for biosynthesis.
In Nostoc, heterocysts are generally intercalary with two polar nodules. This means they are located between other cells in the filament.
Therefore, the correct answer is B) Intercalary.
BETA
