Question

Archaebacteria differ from eubacteria in
(А) Cell membrane structure
(B) Mode of nutrition
(С) Cell shape
(D) Mode of reproduction

Answer 1

Bacteria are the sole members of the Kingdom Monera. They are the most abundant microorganisms. Bacteria occur almost everywhere. Hundreds of bacteria are present in a handful of soil. They also live in extreme habitats such as hot springs, deserts, snow and deep oceans where very few other life forms can survive. Many of them live in or on other organisms as parasites.

Complete answer:
Archaebacteria are special since they live in some of the most harsh habitats such as extreme salty areas halophiles), hot springs (thermoacidophiles) and marshy areas (methanogens). Archaebacteria differ from other bacteria in having a different cell wall structure and this feature is responsible for their survival in extreme conditions.
Now let us match this with the given options:

Cell membrane structure: the archaebacteria do not contain peptidoglycan in their wall but possess lipids in their membrane like that of eukaryotes. Thus, they do not have the same cell wall as that of bacteria. So, this option is correct.
Mode of nutrition: like other bacteria they also have autotrophic as well as heterotrophic mode of nutrition. Thus, this option is not correct.
Cell shape : like other bacteria they possess coccus, bacillus, vibrio and all the shapes. Thus this option is not correct.
Mode of reproduction : They also reproduce by binary fission like all other bacteria reproduce . Thus this option is not correct.

Our required answer is A) cell membrane structure.

Note: Methanogens are present in the gut of several ruminant animals such as cows and buffaloes and they are responsible for the production of methane (biogas) from the dung of these animals. Due to their different kinds of cell wall they are adapted to very harsh habitats.