Question

1. Classification of Microbes – Three domains, General characteristics

2. General features of eukaryotic organisms- fungi and Algae

3. Major Differences between Prokaryotes and eukaryotes. Nomenclature of Microorganisms and classification of microbes based on shape and arrangement. Basic structure of a Prokaryotic cell. Basic Functions and structures of major cellular components of prokaryotic cell like Capsule, Flagella, fimbrae, Pili, Plasmids, cell wall.

Answer 1

HomeworkLib guidelines I can answer 1st question as these are long type questions.

Three domains system is a biological classification given by Carl Woese et al in 1990 that classify microbes into Archaea,bacteria,Eukarya .The method Woese used to identify this “third form of life,” which involved comparing the sequences of a particular molecule central to cellular function, called ribosomal RNA, has become the standard approach used to identify and classify all organisms.

1.Archaebacteria:-a. These bacteria are special since they live in some harsh habitats such as extreme salty areas(halophiles),hot springs(thermoacidophiles) and marshy areas(methanogens).

b.Archaea are prokaryotic cell .They have membranes composed of branched hydrocarbon chains (many also containing rings within the hydrocarbon chains) attached to glycerol by ether linkages.Their cell wall contain no peptidoglycan.

c.Methanogens are present in the gut of several ruminant animals such as cows and buffaloes and they are responsible for the production of methane (bio gas) from the dung of these animals.

d.Archaea contain rRNA that is unique to the Archaea as indicated by the presence molecular regions distinctly different from the rRNA of Bacteria and Eukarya.
e.They are sensitive to few antibiotics that affect eukarya .

2.Bacteria:-

a.Bacteria also known as eubacteria or true bacteria.They are characterised by the presence of a rigid cell wall,and if motile,a flagellum.

b.They are prokaryotic cells.Like the Eukarya, they have membranes composed of unbranched fatty acid chains attached to glycerol by ester linkages.

c.The cell wall of bacteria contains peptidoglycan.

d.Bacteria contain rRNA that is unique to the Bacteria as indicated by the presence molecular regions distinctly different from the rRNA of Archaea and Eukarya.

e.The cyanobacteria (blue green algae) have chlorophyll a similar to green plants and are photosynthetic autotrophs.

3.Eukarya:-

a.They are eukaryotic cells.they have membranes composed of unbranched fatty acid chains attached to glycerol by ester linkages.

b.few organisms contain cell wall with no peptidoglycan .They are resistant to traditional antibacterial antibiotics.

c.Eukarya contain rRNA that is unique to the Eukarya as indicated by the presence molecular regions distinctly different from the rRNA of Archaea and Bacteria.

d.In Eukarya protista is the simple and unicellular eukaryotic organisms like slime moulds ,protozoans.Fungi are unicellular or  multicellular eukaryotic organisms.

e.Plantae and animalia are multicellular eukaryotic organisms.