Biology – Procaryotes Essay, Research Paper

Procaryotes

TECHNOLOGY

Two new technologies have enabled scientists to develop a new classification system. These include the electron microscope, which show fine details of the structure of cells and the development of specific biochemical techniques. These recent developments have found that three genera of eubacteria are so different biochemically from other groups that a new kingdom called the Archaebacteria . These Archaebacteria live in extreme climates i.e. ocean floors near volcanic vents at 1100C or hot sulfur springs. Special equipment was required to improve research of these bacteria, hence recent developments of underwater equipment and technology (e.g. deep sea probes) have enabled scientists to discover the deep sea.

ARCHAEBACTERIA ( Archae ancient )

Methanogens, thermoacidophiles and halobacteria were originally classified under the kingdom of Eubacteria, but however have been placed under the new kingdom of Archaebacteria due to their differing characteristics. The three organisms live in extreme habitats. The differences include:

Different nucleotide sequences of RNA

Different metabolism of carbon compounds

Their cell walls are chemically different and

Their respiratory coenzymes are unique.

METHANOGENS

Are examples of an Archaebacteria. Their extreme habitats include the digestive tracts of animals, swamps and oceans. They convert carbon dioxide and hydrogen produced by other anaerobes (organisms which live in the absence of oxygen) into methane (about 2 billion tonnes per year). They can be used to ferment waste materials in a digestor and the methane gas collected is used for heating, lighting and cooking. This is an example of a symbiotic relationship. Where the methanogens break down food in the digestive track to provide essential nutrients, whilst itself attains a source of energy.

EUBACTERIA

Eubacteria live in a wide variety of habitats and obtain their energy needs in a variety of ways. They inhibit virtually every environment on Earth including the inside of other organisms. The main phyla are organized by how they obtain energy.

HETEROTROPHS

Includes parasites, which absorb nutrients from living organisms and some others as saprobes, which feed on dead organisms or organic wastes. This is because heterotrophs aren t adapted for obtaining capturing the food, which contain the organic molecules required.

AUTOTROPHS

Autotrophs have the ability to photosynthesise and thus create their chemical energy and needs from the suns. They are common in ponds, lakes, streams and moist areas of land. They are composed of chains of bacteria cells, an exception to the rule that Monerans are unicellular. These chains and the existence of Chlorophyll, help provide evidence for bacteria being the ancestors of plants.

CYANOBACTERIA

More commonly known as blue-green algae, are examples of autotrophic Eubacteria. They played the significant role in the transformation from an anoxic to an oxic environment 2 billion years ago. They can be found in a variety of terrestrial and aquatic environments playing a large role in nitrogen fixation. Cyanobacteria may be free-living or in a mutualistic relationship (i.e. with plants).

CHEMOTROPHS

The third phylum is the chemosynthetic autotrophs. These bacteria obtain their energy from chemosynthetic breakdown of inorganic (nonliving matter – no carbon) substances such as sulfur and nitrogen compounds. Some of these bacteria are important in converting nitrogen in the atmosphere to forms that can be used by plants.

NITROGEN-FIXING BACTERIA

This is an example of a chemotrophic eubacteria. All living species need nitrogen for the synthesis of proteins and nucleic acids. While surrounded by nitrogen gas, most species cannot utilise it. They depend on nitrogen fixing organisms to convert atmospheric nitrogen intro forms of nitrogen directly usable by plants nitrates and ammonium ions. Rhizobium is an example of nitrogen fixing bacteria, which lives in the root nodules of legumes.

DEEP SEA BACTERIA

This is another example of a chemotroph. They produce sulfur from hydrogen sulphide and are found in anaerobic lake and ocean sediments. A symbiotic relationship between the bacteria and the animal exists. The bacteria live in or on the animal s body producing nutrients (by chemosynthesis) that both the bacterium and the animal may utilise, from the hydrogen sulphide, which is channelled to the bacteria by the animal. These bacteria make it possible for animals such as tubeworms, clams and mussels to survive an otherwise hostile environment.