Given below are two statements: [2022]
Statement I: Mycoplasma can pass through less than 1 micron filter size.
Statement II: Mycoplasma are bacteria with cell wall.
In the light of the above statements, choose the most appropriate answer from the options given below:
Both Statement I and Statement II are correct
Both Statement I and Statement II are incorrect
Statement I is correct but Statement II is incorrect
Statement I is incorrect but Statement II is correct
(3)
Mycoplasma are organisms that completely lack a cell wall. They are the smallest living cells that can penetrate a 0.2 μm rated filter.
Match the organisms in Column-I with habitats in Column-II: [2019]
| Column-I | Column-II |
| A. Halophiles | (i) Hot springs |
| B. Thermoacidophiles | (ii) Aquatic environment |
| C. Methanogens | (iii) Guts of ruminants |
| D. Cyanobacteria | (iv) Salty area |
Select the correct answer from the options given below.
A-(iv), B-(i), C-(iii), D-(ii)
A-(i), B-(ii), C-(iii), D-(iv)
A-(iii), B-(iv), C-(ii), D-(i)
A-(ii), B-(iv), C-(iii), D-(i)
Which of the following are found in extreme saline conditions? [2017]
Eubacteria
Cyanobacteria
Mycobacteria
Archaebacteria
(4)
Halophiles, a type of archaebacteria, usually occur in extreme saline conditions like salt pans, salt beds, and salt marshes.
Which among the following are the smallest living cells, known without a definite cell wall, pathogenic to plants as well as animals, and can survive without oxygen? [2017]
Pseudomonas
Mycoplasma
Nostoc
Bacillus
(2)
Mycoplasmas are the smallest living cells, known without a definite cell wall. They are pathogenic to both plants and animals and can survive without oxygen.
Which of the following components provides a sticky character to the bacterial cell? [2017]
Nuclear membrane
Plasma membrane
Glycocalyx
Cell wall
(3)
Glycocalyx is the outermost mucilage layer of the cell envelope, which consists of non-cellulosic polysaccharides with or without proteins. It gives sticky character to the cell.
DNA replication in bacteria occurs [2017]
within nucleolus
prior to fission
just before transcription
during S phase
(2)
DNA replicates in bacteria just before they divide by fission.
Methanogens belong to [2016]
eubacteria
archaebacteria
dinoflagellates
slime moulds
(2)
Methanogens belong to archaebacteria. They include methane-producing genera such as Methanobacillus and Methanothrix. Methanogens are obligate anaerobes found in oxygen-deficient environments, such as marshes, swamps, sludge (formed during sewage treatment), and the digestive systems of ruminants. Mostly, they obtain their energy by reducing carbon dioxide and oxidising hydrogen, with the production of methane.
The primitive prokaryotes responsible for the production of biogas from the dung of ruminant animals, include the [2016]
methanogens
eubacteria
halophiles
thermoacidophiles
Archaebacteria differ from eubacteria in [2014]
cell membrane structure
mode of nutrition
cell shape
mode of reproduction
(1)
The archaebacteria are the 'ancient' bacteria that include extremophiles like methanogens, halophiles, and thermophiles. They represent some of the most ancient of life forms that persist today. They have both eubacterial and eukaryotic characters besides the features unique to them. Their mode of reproduction, nutrition, and cell shape and size resembles a typical eubacteria. Their cell walls are made of a variety of polymers but do not contain peptidoglycan, unlike eubacteria. Lipids of their cytoplasmic membranes are ether-linked, unlike eubacteria, which contain glycerol ester lipids in their cell membrane.
