Biological Classification And System Of Classification Question 53
Question: Nostoc is characteristic in having
[MP PMT 1998]
Options:
A) Cellulose cell wall
B) Uniflagellated zoospores
C) Chlorophyll ’e'
D) Sexual reproduction
Show Answer
Answer:
Correct Answer: A
Solution:
Nostoc is free-living nitrogen-fixing cyanobacteria having cells arranged in beadlike chains (trichomes) that are grouped together in a gelatinous mass (Nostoc balls).
Each cell is surrounded by a cellulose cell wall.
They fix atmospheric nitrogen in specialized cells called heterocysts.
Nostoc contains two pigments, blue phycocyanin and red phycoerythrin, as well as chlorophyll.
It does not have chlorophyll ’e’ which is a characteristic feature of Xanthophyceae.
The cells do not possess flagella but are motile by a swaying motion. Reproduction is only by vegetative and asexual methods.
BETA
