Question

The organisms without a cell wall and can live without oxygen are
A. Thermoacidophiles
B. Methanogens
C. Archaebacteria
D. Mycoplasma

Answer 1

Hint:They are the smallest self-replicating organisms with the smallest genomes. They have no flagella, produce no spores, and are gram negative.

Complete Answer:
All organisms are made up of cells or cell aggregates. Cells vary in shape, size and activity or function. On the basis of the presence or absence of a nuclear membrane and other organelles, the cells and therefore organisms may be called eukaryotic or prokaryotic.

The cell wall is found outside of the cell membrane and is present in plants, fungi, bacteria, algae and archaea. It provides a structural framework to sustain plant growth in plants and serves as the first line of protection against pathogens.

Thermoacidophiles are archaebacteria that can typically be found in very acidic conditions at high temperatures. Methanogens are a monophyletic group of anaerobic microorganisms belonging to the Archaea domain. These lithotrophic microorganisms are commonly distributed in oxygen-free ecosystems and are the only major biological sources of methane.

Mycoplasma is a genus of bacteria that forms the simplest and smallest of free living prokaryotes. Mycoplasmas are usually differentiated from other bacteria by their small size and the absence of a cell wall. They live as saprophytes or parasites, and they can survive without oxygen.

Thus, the correct answer is option D i.e., Mycoplasma.

Note:Mycoplasmas are bacteria that are commonly present in association with mucous membranes in all mammalian organisms. Owing to the lack of cell walls, they can be immune to antibiotics including penicillin.