Microbiology and Nitrogen Cycle

Without the constraints of the conserved molecule peptidoglycan, archaeal cell wall may be quite diverse. Methanogenic archaea possesses pseudomurein [Peptidoglycan like polymer which is cross linked with L –Amino acids].

 Correct answer- 2) Acetogenesis is a type of microbial metabolism that uses hydrogen (H2) as an electron donor and carbon dioxide (CO2) as an electron acceptor to produce acetate. Bacteria that can synthesize acetate autotrophically are called homoacetogens. Carbon dioxide reduction in all homoacetogens occurs by the acetyl-CoA pathway. This pathway is also used for carbon fixation by autotrophic sulfate-reducing bacteria and hydrogenotrophic methanogens. Often homoacetogens can also be fermentative, using the hydrogen and carbon dioxide produced as a result of fermentation to produce acetate, which is secreted as an end product. Anammox stands for anaerobic ammonia oxidation and the organisms responsible were relatively Annamox means anaerobic ammonia oxidation. This metabolism occurs in members of Plactomycetes (e.g. Brocadia annamoxidans) and involves coupling of ammonia oxidation to nitrate reduction. Annamox organisms are autotrophs and can fix CO2. Due to this property, these organisms can be used in industry to remove nitrogen in wastewater treatment processes. Syntrophy is the pairing of multiple species occurs in order to achieve chemical reaction which on its own will be energetically unfavorable. In Syntrophomonas, alone, the oxidation of butyrate to acetate and hydrogen gas is energetically unfavorable. But, when a hydrogenotrophic (hydrogen-using) methanogen is present the use of the hydrogen gas will significantly lower the concentration of hydrogen (down to 10−5 atm) and thereby shift the equilibrium of the butyrate oxidation reaction under standard conditions (ΔGº’) to non-standard conditions (ΔG’). Methylotrophy refers to the ability of an organism to use C-1 compounds as energy sources. These compounds are methanol, methyl amines, formaldehyde and formate. Several other less common substrates may also be used for metabolism, all of which lack carbon-carbon bonds. Examples are, bacteria Methylomonas and Methylobacter.

Bacteriostats are biological or chemical agents which stop bacteria from reproducing, but not necessarily harming them.

This is the correct answer as mustard is not leguminous.

This is the correct answer. Blue-green algae, apart from rhizobium bacteria, can fix free nitrogen.

Clostridium is rod-shaped bacteria that is toxic in nature & causes flabby muscular paralysis; yYeast is eukaryotic microorganism (fungi) used in fermentation to convert carbohydrates to carbon dioxide & alcohol; myxomycetes are found in forest areas on dead leaves & have both dry & wet spores; Rhizobium is gram-negative bacterium of soil that helps in nitrogen fixing; Mycorrhizae are the group of fungi that form mutual beneficial relation with other plants.

Mycoderm bacteria are used in conversion of sugar and sugary materials into acetic acid/vinegar.

Both Assertion and Reasoning are true and related. Fertilizers like ammonium nitrites are prepared by this process.

Nitrification involves oxidation of nitrogen compounds.  The decomposers carry out a process called deamination which results in the release of ammonia. Ammonia undergoes oxidation to give nitrates.

Rhodospirillum is a genus of purple non-sulphur photoautotrophic bacteria of the family Rhodospirillaceae.

Myxobacteria and Cytophagales are called gliding bacteria on the basis of their gliding mobility on solid surfaces.

Beggiatoa is a genus of chemosynthetic filamentous sulphur-oxidizing bacteria.

Lactobacillus and Listeria are non-spore forming rods.

Lactobacillus is a facultative anaerobe.

Rhodospirillum is a purple non-sulphur bacterium.