Kingdom Classification - Monera

Characteristics

Unicellular: Organisms in this kingdom are single-celled.
Prokaryotic: They lack a true nucleus and other membrane-bound organelles.
Cell Wall: Most have a cell wall, but it is not made of cellulose.
Nutrition: Can be autotrophic (photosynthetic or chemosynthetic) or heterotrophic.
Reproduction: Primarily by binary fission.

Bacterial cells have a simple but robust structure that enables them to thrive in diverse environments.

External Structures:
- Capsule/Glycocalyx: An outer layer that protects the cell from dehydration and phagocytosis.
- Flagella: Long, whip-like appendages for motility.
- Pili and Fimbriae: Hair-like appendages for attachment and conjugation.
Cell Envelope:
- Cell Wall: Provides structural support and protection. Composed of peptidoglycan.
- Plasma Membrane: A phospholipid bilayer that regulates the passage of substances.
Internal Structures:
- Cytoplasm: The gel-like substance that fills the cell.
- Nucleoid: The region containing the bacterium's genetic material (a single, circular chromosome).
- Ribosomes: Responsible for protein synthesis.
- Plasmids: Small, circular, extrachromosomal DNA molecules that often carry genes for antibiotic resistance.

[Diagram of a Bacterial Cell]

The Kingdom Monera is divided into two sub-kingdoms: Archaebacteria and Eubacteria.

Archaebacteria:
- These are ancient bacteria that live in extreme environments.
- Their cell walls lack peptidoglycan.
- Examples: Methanogens (produce methane), Halophiles (live in salty environments), Thermoacidophiles (live in hot, acidic environments).
Eubacteria:
- These are "true" bacteria.
- Their cell walls are made of peptidoglycan.
- Examples: Cyanobacteria (blue-green algae), Lactobacillus, E. coli.

Shape: Bacteria can have various shapes:
- Cocci: Spherical (e.g., Streptococcus)
- Bacilli: Rod-shaped (e.g., Lactobacillus)
- Spirilla: Spiral-shaped (e.g., Spirillum)
- Vibrio: Comma-shaped (e.g., Vibrio cholerae)

Food Production: Used in making yogurt, cheese, buttermilk, and vinegar.
Medicine: Used to produce antibiotics (e.g., Streptomycin) and vaccines.
Agriculture: Nitrogen-fixing bacteria (e.g., Rhizobium) convert atmospheric nitrogen into a usable form for plants, enriching soil fertility.
Decomposition: Decomposers break down dead organic matter, recycling nutrients in the ecosystem.
Bioremediation: Used to clean up oil spills and other pollutants.

Diseases: Cause various diseases in humans (e.g., Cholera, Tuberculosis, Typhoid), animals, and plants.
Food Spoilage: Cause food to rot and become unfit for consumption.
Denitrification: Some bacteria convert nitrates back into atmospheric nitrogen, reducing soil fertility.