Archaebacteria: Definition, Characteristics, Types, Nutrition, and, Respiration

The word Archaea comes from the Ancient Greek word meaning ancient things. the first observed archaea were living in harsh environments such as hot springs and salt lakes. Archaea are found in almost every habitat, including soils, oceans, and marshlands. They are found in the gut, mouth, and skin. these are old bacteria. These are the organisms when the first life originated. these are the first organisms as they are capable of surviving in extreme conditions e,g in hot conditions at almost 100 degrees, highly acidic conditions i.e. high PH and high salt areas.
Archaebacteria Characteristics
Archaebacteria have several characteristics
1. the Archaebacteria are primitive from an evolutionary point of view
2. they are considered the oldest living fossils
3. the Archaebacteria are prokaryotic organisms
4. Archaebacteria have cell membranes made up of branched lipids and hydrocarbons.
5. their cell wall is made up of complex polysaccharides and complex polypeptides.
6. the nucleoid is present
7. Peptidoglycan is absent in the cell wall of Archaebacteria.
8. Mostly behave as obligate anaerobes i.e oxygen is a poison to these bacteria.

Bacteria: Asexual Reproduction and Genetic Recombination (Parasexuality)

Sexual Reproduction in Bacteria
Sexuality in bacteria was first discovered by Tatum and Lederberg in 1947 in Escherichia coli. Gamete production and fusion are not present in bacteria. The only thing which happens in bacteria is genetic recombination. It means variation is there that does not involve gamete formation. Thus sexual reproduction in bacteria occurs by a method called Parasexuality. As a result, bacteria do not have true sexual reproduction; instead, genetic recombination occurs.
Genetic Recombination (Parasexuality)
There is no gamete formation, no gametic fusion only there is genetic recombination present in bacteria. Thus there is the transfer of genetic material from one bacteria to another bacteria, this method of genetic recombination is known as Parasexuality.

Bacteria: Nutrition and its Types, Autotrophic Nutrition and Heterotrophic Nutrition

A. Phototrophs: the bacteria which use light energy as a source of energy are known as photo-Autotrophs. It is of two types
1. Green sulphur bacteria 2. Purple Sulphur bacteria
1. Green sulphur bacteria: these are small nonmotile, rod-shaped bacteria that are anaerobic photoautotrophs. they contain a pigment called Chlorobium chlorophyll also known as Bacterioviridin that is responsible for absorbing light energy. these bacteria use H2S or other reduced inorganic sulphur compounds as electron donors.e,g Chlorobium, etc
2. Purple Sulphur bacteria: These are also autotrophs and their photosynthetic pigments are bacteriochlorophyll a or b. e,g Thiospirillum, and Amoebobacter.

Bacteria: Definition, Size,Distribution and Classification

Distribution of Bacteria
Bacteria are found in all-natural ecosystems and have a worldwide distribution. Their distribution is because they can withstand great extremes of temperature, moisture, acidity, and salinity and are adapted to a wide variety of energy sources. They occur in the atmosphere to a height of about six kilometers and on the seafloor five kilometers below the mean sea level. they exist in hot springs and can also survive below freezing points in the Atlantic ice. Bacteria live at the pressure of one atmosphere but they can tolerate the pressure of 3000-6000 atmospheres. some bacteria can live in presence of oxygen while some live without oxygen. the great success of bacteria is due to their small size, rapid reproductive rate, ability to survive under adverse conditions, and metabolic adaptations.

Monera: Definition and Characteristics

Monera Definition
The Monera is derived from the Greek word Moneres means single or solitary. The kingdom monera is said to be the oldest living thing on the planet, which is made up of unicellular creatures having a prokaryotic cell structure. they’re single-celled organisms that don’t have a genuine nuclear membrane (prokaryotic organisms).