Kingdom Monera

Key Points to Remember

  • Members of Kingdom Monera are prokaryotes (no true nucleus or organelles).
  • Their cell wall contains peptidoglycan (except in Archaea).
  • The genetic material is circular DNA, often with small extra loops called plasmids.
  • Some have flagella (for movement) or capsules (for protection).
  • They can be autotrophic (make their own food) or heterotrophic (depend on others for food).
  • Reproduction mostly happens by binary fission (simple cell division).
  • Monera is divided into Eubacteria (true bacteria) and Archaebacteria (ancient bacteria).

Keywords

Prokaryotic, Binary Fission, Cyanobacteria, Archaebacteria, Peptidoglycan.

Kingdom Monera – The Simplest Life Forms

The Kingdom Monera includes the most primitive and microscopic organisms on Earth — mainly bacteria and archaea.
These living things do not have a true nucleus or membrane-bound organelles, making them prokaryotic.

They are found everywhere — in soil, water, air, hot springs, deep oceans, and even inside living organisms.

Characteristics of Kingdom Monera

1. Cell Type and Structure

  • Cells are prokaryotic, meaning no nucleus or membrane-bound organelles.
  • Genetic material is present in a single circular DNA loop (nucleoid).
  • Some bacteria also have plasmids — small extra DNA loops that carry special traits.
  • Cell wall is made of peptidoglycan (except in Archaea, which have proteins or pseudo-peptidoglycan).
  • Some bacteria form a capsule for extra protection.
  • Flagella may be present for movement.

2. Mode of Nutrition

Organisms in Monera can feed in different ways:

A. Autotrophic (Self-feeding)

They make their own food.

  • Photosynthetic bacteria (like Cyanobacteria) use sunlight to perform photosynthesis.
  • Chemosynthetic bacteria (like Nitrosomonas and Nitrobacter) get energy from chemical reactions.

B. Heterotrophic (Feeding on others)

They depend on other organisms for food.

  • Saprophytic bacteria (like Bacillus) feed on dead and decaying matter.
  • Parasitic bacteria (like Mycobacterium tuberculosis) live inside host organisms.

3. Reproduction

  • The main mode is binary fission, a type of asexual reproduction where one cell divides into two identical cells.
  • Some bacteria form endospores to survive harsh conditions.
  • Genetic variation happens through:
    • Conjugation – DNA exchange between two cells
    • Transformation – Uptake of DNA from the environment
    • Transduction – DNA transfer by viruses

Classification of Kingdom Monera

A. Archaebacteria (Ancient Bacteria)

These are primitive organisms that live in extreme environments like hot springs, salt lakes, and deep oceans.
Their cell walls lack peptidoglycan, making them unique.

Types of Archaebacteria:

  • Methanogens (Methanobacterium) – produce methane gas; live in marshes and animal guts.
  • Halophiles (Halobacterium) – thrive in salty environments.
  • Thermoacidophiles (Sulfolobus) – live in hot, acidic conditions.

B. Eubacteria (True Bacteria)

These are common bacteria found in soil, water, and inside living organisms.

Types of Eubacteria:

  • Cyanobacteria (Blue-green algae) – photosynthetic bacteria such as Nostoc and Anabaena.
  • Gram-positive bacteria – thick cell walls, e.g., Streptococcus, Staphylococcus.
  • Gram-negative bacteria – thinner cell walls, e.g., E. coli, Salmonella.
  • Nitrogen-fixing bacteria – help plants by converting nitrogen, e.g., Rhizobium.

Significance of Kingdom Monera

  • Decomposers: Recycle nutrients by breaking down organic matter.
  • Nitrogen Fixation: Help in soil fertility and plant growth.
  • Industrial Use: Used in fermentation, antibiotic production, and biotechnology.
  • Ecological Role: Maintain balance in ecosystems by cycling nutrients.

Summary Table

Feature

Kingdom Monera

Cell Type

Prokaryotic

Cell Structure

No nucleus, circular DNA, plasmids

Cell Wall

Peptidoglycan (except Archaea)

Nutrition

Autotrophic & Heterotrophic

Reproduction

Binary Fission

Examples

Bacteria, Cyanobacteria, Archaea

Conclusion

The Kingdom Monera forms the foundation of life on Earth.
These tiny organisms may be simple, but they play a huge role in maintaining ecological balance, supporting plant life, and driving many natural processes

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