Test: Kingdom Monera (NCERT) - NEET MCQ

Bacteria are grouped under four categories based on their shapes: the spherical coccus (pl.: coccl), the rod-shaped bacillus (pi.: bacilli), the comma-shaped vibrium (pl.: vibrio) and the spiral spirillum (pl.: spirilla).

The Mycoplasma are organisms that completely lack a cell wall. They are the smallest living cells known and can survive without oxygen. Many mycoplasma are pathogenic in animals and plants.

Bacteria are grouped into four categories based on their shape: spherical (Coccus, pl. cocci), rod-shaped (Bacillus, pl. bacilli), comma-shaped (Vibrium, pl. vibrio), and spiral (Spirillum, pl. spirilla).

(i) They are included in the group Archaebacteria.

Correct. The content mentions, "Archaebacteria differ from other bacteria in having a different cell wall structure."
(ii) They are responsible for the production of biogas in gobar gas plants.

Correct. The content states, "Methanogens are present in the gut of several ruminant animals...and they are responsible for the production of methane (biogas) from the dung of these animals."
(iii) They live in hot sulphur springs.

Incorrect. The content says, "These bacteria live in some of the most harsh habitats such as...hot springs (thermoacidophiles) and marshy areas (methanogens)." Methanogens are not specified to live in hot sulphur springs; thermoacidophiles do.
(iv) They are present in the gut of several ruminant animals such as cows and buffaloes

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

It is filamentous blue green algae- Nostoc

Both Archaebacteria and eubacteria are classified under kingdom monera.

Cyanobacteria have chlorophyll-a, similar to green plants, which allows them to perform photosynthesis. They are photosynthetic autotrophs and can be unicellular, colonial, or filamentous algae.

Mycoplasma are unique among bacteria because they completely lack a cell wall, making them the smallest living cells known. They can survive without oxygen, and many of them are pathogenic in animals and plants.

Cyanobacteria can fix atmospheric nitrogen in specialised cells called heterocysts, e.g., Nostoc and Anabaena. Chemosynthetic autotrophic bacteria oxidise various inorganic substances such as nitrates, nitrites and ammonia and use the released energy for their ATP production. They play a great role in recycling nutrients like nitrogen, phosphorous, iron and sulphur.

To identify the correct statements about bacteria reproduction:

- A: Bacteria reproduce mainly by fission: Correct. Binary fission is the primary method of bacterial reproduction.
- B: Bacteria reproduce by production of gametes: Incorrect. Bacteria typically reproduce asexually, not through the production of gametes.
- C: Under unfavorable conditions, Bacteria produce spores: Correct. Bacteria form spores as a survival strategy in harsh environments.
- D: Bacteria reproduce by a sort of sexual reproduction:  Correct. Bacteria usually  reproduce asexually and reproduce by a sort of sexual reproduction by adopting a primitive type of DNA transfer from one bacterium to the other.

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. Chemosynthetic autotrophic bacteria oxidise various inorganic substances such as nitrates, nitrites and ammonia and use the released energy for their ATP production. They play a great role in recycling nutrients like nitrogen, phosphorous, iron and sulphur.

Heterotrophic bacteria are most abundant in nature. The majority are important decomposers. Many of them have a significant impact on human affairs. They are helpful in making curd from milk, production of antibiotics, fixing nitrogen in legume roots, etc.

Monera kingdom includes prokaryotes - mycoplasma bacteria, actinomycetes and cyanobacteria or blue greet algae. Alongwith fungi, they are decomposers and mineralisers of the biosphere.

To identify the incorrect statement regarding bacteria:

- A: Bacteria are the most abundant microorganisms.
- B: Bacteria live in extreme habitats where very few other life forms can survive.
- C: Bacteria as a group show the most extensive metabolic diversity.
- D: They are obligate intracellular parasites.

The incorrect statement is: D: They are obligate intracellular parasites.

Explanation: Bacteria can be classified as intracellular or extracellular, with many living freely outside cells. While some bacteria can be obligate intracellular parasites, not all bacteria exhibit this behavior.

The correct answer is D: NOSTOC

Nostoc is a bacteria (prokaryote) where as all the other three ( Penicillium , Agaricus , Volvox ) are eukaryotes and have a nucleus and nuclear membrane