Introduction to Kingdom Monera

Introduction

We all have heard about bacteria but do you know that it belongs to Kingdom Monera? Bacteria are microscopic organisms that can survive in multiple environments. These can be beneficial and harmful at the same time. Bacteria lack a nucleus and have a few cell organelles only.

All bacteria have an outer cell wall and an inner cell membrane. Some moneran like mycoplasma doesn’t have a cell wall, while others are covered with a capsule. It has flagella structures that have a long whip-like reflection. The short whip extensions are pili which surround the bacteria’s outer surface.  

Bacteria can exhibit autotrophic or heterotrophic nutrition modes. Autotrophic bacteria obtain nutrition from inorganic substances. These substances derive carbon and hydrogen from atmospheric carbon dioxide, ammonia, hydrogen sulfide and hydrogen. The heterotrophic bacteria obtain nutrition from the external organic materials and are categorised as parasites, symbionts, and saprotrophs.

What Is The Kingdom Monera?

Ernst Haeckel proposed the Monera as a phylum for the first time in 1866. After that, Édouard Chatton elevated the phylum to the level of the kingdom in 1925. Robert Whittaker’s five-kingdom classification scheme, published in 1969, was the most widely accepted.

The prokaryote family includes the kingdom monera. These organisms are one of the oldest known species since they lack a real nucleus. Furthermore, their DNA is not contained within the nucleus. These organisms are only found in humid habitats and . While membrane-bound organelles do not exist, they can be discovered in the snow, as parasites on other creatures, deep oceans, hot springs, and other places. Bacillus and Mycobacterium are two examples.

Different Shapes Of Bacteria

• Vibrios: A  comma-shaped bacteria, which was originally defined in 1854
• Cocci: These bacteria are spherical or oval. These can be micrococcus (single), diplococcus (in pairs), tetracoccus (in fours), staphylococcus (in grapes-like structure), and streptococcus (in chains)
•  Bacilli: These are in the shape of rods with or without flagella
• Filament: These bacteria have bodies made up of filaments like fungal mycelia
• Spirillum: These bacteria are coiled or spiral-shaped and have rigid forms due to the spiral structure and carry flagella at one or both ends
• Budded: These bacteria have swollen bodies at places
• Stalked: These bacteria have a shape like a stalk

What Are The Types Of Monera?

There are three different sub-kingdoms of monera. These are:

Archaebacteria: These are some of the ancient microorganisms found in harsh environments such as hot springs (thermoacidophiles), marshy places (methanogens), and salty areas (salinophiles) /(halophiles). Autotrophic bacteria are those that feed on their own waste. Their cell wall structure differs from that of other bacteria in order to allow them to survive in hostile environments. These have a t-RNA and rRNA nucleotide sequence.

Eubacteria: The term “true bacteria” refers to these organisms. Their cell wall is stiff and made up of peptidoglycans. It can be classed as gram-positive or gram-negative based on stains. It is determined by the kind of cell wall and the presence of stains. These have pili appendages on their cell surfaces that aid in sexual reproduction. It also aids the infection in attaching to the host. Rhizobium, Clostridium, and other bacteria are some examples. They play a significant role in the economy, agriculture, and medicine.

Cyanobacteria: These are “blue-green algae” and are photosynthetic. These organisms contain phycobilins, carotenoids, and chlorophyll. They are found in aquatic regions. Some cyanobacteria can also fix atmospheric nitrogen. Some of the examples for these bacteria are Anabaena, Spirulina, Nostoc, etc. However, because of their ability to photosynthesise, some Cyanobacteria were previously classed as Plantae.

Structure

The structural format of the bacteria present here has the categorisation in these options:

• • Cell wall: All bacterial cells have the covering of a rigid cell wall that is made of polysaccharides, proteins, and lipids
  • Cytoplasm: This fluid consists of vitamins, salts, carbohydrates, and enzymes

• Capsules: This thin capsule structure is present outside the cell wall. It has polysaccharides and amino acids.

Another important part of the structure is nucleoids, plasmids, flagella, and plasma membrane.

Characteristics of Kingdom Monera

• The organism comprises 70S ribosomes
• Organelles such as golgi bodies, mitochondria, lysosomes, plastids, endoplasmic reticulum, etc. are absent
• Their rigid cell wall is made of peptidoglycan
• They are unicellular organisms
• They are known to be environmental decomposers
• The DNA is naked as they aren’t included in the nucleus
• The approach of reproduction carried out by these organisms is asexual in nature. The same is done via binary fission or budding
• These organisms have different modes of nutrition such as autotrophic, parasitic, saprophytic, and heterotrophic
• The locomotory organ in this organisms is the flagellum

Conclusion:

The kingdom monera is an essential topic in the CBSE class 11th biology syllabus. Hence, students need to prepare all about it, types of monera, etc. The different monera kingdom examples further help understand the detailed characteristics of the kingdom monera.