Microbial Metabolism

Noncyclic photophosphorylation is absent in bacterial photosynthesis.

The methanogens oxidizes H₂ as a sole source of energy while transferring the electrons from H₂ to CO₂ in its reduction to methane.
Iron bacteria oxidize Fe^₊₊ as energy source to Fe⁺⁺⁺.

Entner–Doudoroff pathway occurs only in prokaryotes.
Entner–Doudoroff pathway has a net yield of 1 ATP, 1 NADH and 1 NADPH for every glucose molecule metabolized.

Very few gram-positive bacteria have ability to oxidize glucose by Entner–Doudoroff pathway. Enterococcus faecalis is an example of gram-positive bacteria having ability to oxidize glucose by Entner–Doudoroff pathway.

Entner-Doudoroff pathway was first reported by Michael Doudoroff and Nathan Entner in Pseudomonas Saccharophila.

Ubiquinones (also known as Coenzyme Q) are non-protein electron carriers located in the inner mitochondrial membrane.

Gallionella oxidize Fe⁺⁺ as a source of energy for lithoautotrophic growth.
Alcaligenes are hydrogen bacteria, i.e., they oxidize H₂ as an energy source.
Rhodospirillum are carboxydobacteria, i.e., they oxidize CO to CO₂ using an enzyme carbon monoxide dehydrogenase.
Nitrobacter oxidizes NO₂ to NO₃.

Site of photosynthesis in cyanobacteria is thylakoids.
Site of photosynthesis in green sulphur bacteria is chlorosomes.
Site of photosynthesis in purple bacteria is chromatophores.

Assertion as well as reason statements are correct and R is correct explanation of A.
During aerobic respiration, lesser number of ATPs is produced in eukaryotes (34 molecules of ATP) than in prokaryotes (38 molecules of ATP). This is because of the reason that, in eukaryotes, some energy is lost when electrons are shuttled across the mitochondrial membranes that separate glycolysis (in cytoplasm) from the electron transport chain. No such separate mechanism exists in prokaryotes.

In dissimilative sulfur reduction, elemental sulfur is reduced to hydrogen sulfide. Dissimilative sulfur reducers reduce elemental sulfur to hydrogen sulfide.
Campylobacter and Desulfuromonas are dissimilative sulfur reducers.

Bacillus, Lactobacillus, Streptococcus: All the three yield lactic acid as fermentation end product.

Desulfobacter uses CO₂ from reverse TCA cycle as major C-Source.

Enterobacter yields ethanol, lactic acid, formic acid, butanediol, acetoin, CO₂, and H₂ as fermentation end product.
Escherichia yields ethanol, lactic acid, succinic acid, acetic acid, CO₂, and H₂ as fermentation end product.
Saccharomyces yields ethanol and CO₂ as fermentation end products.
Salmonella yields ethanol, lactic acid, succinic acid, acetic acid, CO₂, and H₂ as fermentation end product.

Gluconobacter species are used for oxidation of D-sorbitol into L-sorbose in the commercial production of vitamin C (ascorbic acid).
Various strains of Aspergillus niger are used in the industrial preparation of citric acid.
Streptococcus thermophilus is used in making reduced-fat cheese with similar characteristics to regular full-fat cheese.
Glycerol is a major by-product of ethanol fermentation by Saccharomyces cerevisiae.

Final electron acceptor in aerobic respiration is molecular oxygen.
The final electron acceptors in anaerobic respiration include NO₃^–, SO₄^2–, and CO₃^2–.
The final electron acceptor in fermentation is an organic molecule.