Prokaryotes

Types of Typing Methods

  • Biochemical Typing: Variations in biochemical tests useful for species differentiation.

  • Serological Typing: Differences in antibodies binding to cell membrane proteins and carbohydrates.

  • Phage Typing: Sensitivity differences to specific phages.

  • Antibiograms: Sensitivity variations to antibiotics.

  • Molecular Typing: Variation in DNA sequences.

Electron Transport

  • Final Electron Acceptors: Molecule receiving electrons at the end of an electron transport chain.

  • Initial Electron Donors: Substances donating electrons in redox reactions.

Symbiotic Relationships

  • Nitrogen-fixing bacteria form mutualistic associations with plants, converting atmospheric nitrogen into usable forms, while receiving carbohydrates and protection in return.

Bacterial Survival Requirements

  • Hydrogen-oxiding Bacteria: Require hydrogen (H2) to survive.

  • Aerobic Bacteria: Obligate aerobes and microaerophiles require oxygen for survival.

Microbial Groups in Nitrogen Cycle

  • **Groups Involved:

    • Nitrogen Reducing Bacteria

    • Denitrifiers

    • Nitrogen Fixers

    • Cyanobacteria & Purple Bacteria

    • Nitrifying Bacteria**

Energy Generation in Bacteria

  • Sulfur Reducing Bacteria: Generate ATP via anaerobic respiration, coupling electron donor oxidation with sulfur compound reduction.

  • Sulfur Oxidizing Bacteria: Generate ATP by oxidizing inorganic sulfur compounds through chemosynthesis or photosynthesis.

Photophosphorylation in Bacteria

  • Non-Cyclic Photophosphorylation: Produces NADPH and ATP, uses two photosystems, sulfur compounds as electron donors.

  • Cyclic Photophosphorylation: Produces only ATP, uses one photosystem, no oxygen release.

  • Purple and Green Non-Sulfur Bacteria only use cyclic phosphorylation due to lack of water-splitting mechanism.

Bioleaching Process

  • Bioleaching Mechanism: Microorganisms dissolve metals from ores directly by attaching and breaking down minerals or indirectly by producing acids like sulfuric acid.

  • Cyanobacteria Structure: Form mats, secrete extracellular polymeric substances (EPS) for cohesion and surface binding.

Final Electron Acceptors

  • Aerobes: Use O2 as the final electron acceptor.

  • Anaerobic Groups:

    • Sulfate-reducing Bacteria: Use SO4, producing hydrogen sulfide.

    • Methanogens: Use CO2 to produce methane (CH4).

    • Some use nitrate (NO3), reducing it to nitrogen gas (N2).

Prokaryotic Groups by Waste Products

  • Methanogens: Methane (CH4)

  • Green & Purple Sulfur Bacteria: Elemental sulfur (S0)

  • Sulfur Oxidizing Bacteria: Sulfuric acid (H2SO4)

  • Nitrite-Oxidizing Bacteria: Nitrate (NO3)

  • Denitrifying Bacteria: Dinitrogen gas (N2)

  • Cyanobacteria: Oxygen (O2)