Question

Select the correct statements.

a. Methanogens are archaebacteria which produce methane in marshy areas.
b. Nostoc is a filamentous BGA which fixed atmospheric $N_2$.
c. Chemosynthetic autotrophic bacteria synthesise cellulose from glucose.
d. Mycoplasma lack cell wall and can survive without oxygen.

• A. a, b, d
• B. b, c, d
• C. b, c
• D. a, b, c

Answer 1

The correct option is A a, b, d

Correct statements

Statement a: Methanogens are archaebacteria which produce methane in marshy areas.

Elaboration: Methanogens are present in the rumen of cattles and produce methane from cellulose under anaerobic conditions. These bacteria are utilised in the production of biogas. These bacteria are also responsible for methane production in marshy areas which have anaerobic conditions. Hence, the given statement in option a is correct.

Statement b: Nostoc is a filamentous BGA which fixed atmospheric $N_2$.

Elaboration: Some cyanobacteria (blue green algae or BGA) have the abiity to fix atmospheric nitrogen using specialised cells called heterocysts. For example, filamentous blue green algae, Nostoc. Hence, the given statement in option b is correct.

Statement d: Mycoplasma lack cell wall and can survive without oxygen.

Elaboration: Mycoplasma are the simplest form of prokaryotes and they lack cell walls due to which they are pleomorphic. They can survive even in the absence of oxygen. Hence, the given statement in option d is correct.