Test: Kingdom Monera - 2 - NEET MCQ

Methanogens , Halophiles , Thermoacidophils , all belong to ARCHAEBACTERIA. They are primitive organisms which means they were the first to inhabit earth . They are often called LIVING FOSSILS. Methanogens are found in Rumen of cattles , Halophiles are found in salt lakes , Thermoacidophils are found in hot sulphur springs and Archaebacteria are found in some of the harsh climatic conditions where no other life form could survive.

Line in NCERT: "These bacteria 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)."

These are a result of blue-green algae, which are actually bacteria (cyanobacteria). Some algal blooms are the result of an excess of nutrients (particularly phosphorus and nitrogen) in waters and higher concentrations of these nutrients in water cause increased growth of algae and green plants.

Cyanobacteria is the modern name of Myxophyceae. It is also called blue-green algae. It is a prokaryotic photosynthetic organism.

Line in NCERT: "The cyanobacteria (also referred to as blue-green algae) have chlorophyll a similar to green plants and are photosynthetic autotrophs."

Bacteria reproduce mainly by fission. Sometimes, under unfavourable conditions, they produce spores. They also reproduce by a sort of sexual reproduction by adopting a primitive type of DNA transfer from one bacterium to the other

Line in NCERT: "Bacteria reproduce mainly by fission. They also reproduce by a sort of sexual reproduction by adopting a primitive type of DNA transfer from one bacterium to the other."

cyanobacteria (also referred to as blue-green algae) have chlorophyll a similar to green plants and are photosynthetic autotrophs.The cyanobacteria are unicellular, colonial or filamentous, freshwater/marine or terrestrial algae. The colonies are generally surrounded by gelatinous sheath. They often form blooms in polluted water bodies. Some of these organisms can fix atmospheric nitrogen in specialised cells called heterocysts, e.g., Nostoc and Anabaena.

Line in NCERT: "The cyanobacteria (also referred to as blue-green algae) have chlorophyll a similar to green plants and are photosynthetic autotrophs."

Mycoplasma is a prokaryote having no cell wall so they are also called "bacteria with their coats off".They are resistant to penicillin because penicillin acts as a cell wall and they are wall less.

Line in NCERT: "The Mycoplasma are organisms that completely lack a cell wall."

Fission or Binary fission ("division in half") is a kind of asexual reproduction. It is the most common form of reproduction in prokaryotes such as bacteria. It occurs in some single-celled Eukaryotes like the Amoeba and the Paramoecium. In binary fission, DNA replication and segregation occur simultaneously.

Line in NCERT: "Bacteria reproduce mainly by fission (Figure 2.3)."

- Correct Answer: B: BOTH II AND III
- Explanation:

STATEMENT I : Halophiles are eubacteria living  in salty areas - HALOPHILES are archaebacteria not eubacteria 
- Statement II: Methanogens are indeed abundant in the guts of ruminants. These are a group of archaea that produce methane as a byproduct of metabolism in the digestive systems of ruminant animals like cows.
- Statement III: Thermoacidophiles are bacteria that thrive in hot, acidic environments like hot springs, demonstrating their ability to survive in extreme conditions.

Line in NCERT: "These bacteria 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)."

Cyanobacteria often form blooms in polluted water bodies. Some of these organisms can fix atmospheric nitrogen in specialised cells called heterocysts, e.g., Nostoc and Anabaena

Line in NCERT: "they often form blooms in polluted water bodies."

Chemosynthetic autotrophic bacteria oxidize inorganic substances for their ATP production.

Line in NCERT: "Chemosynthetic autotrophic bacteria oxidise various inorganic substances such as nitrates, nitrites and ammonia and use the released energy for their ATP production."