Question

Know these!!!: 3 domains of life • How spontaneous generation was refuted (and the process of science for that) Other concepts to know: • Cell theory (what it says, what evidence supports it) Relative sizes (what can interact with what?) Very basic overview of types of microbes Common features of all cells

Answer 1

Depending upon the characteristics of the organism, all organisms can be divided into three domains of life.

The three domains in life are as follows:-

1. Archaea

2. Eubacteria (bacteria)

3. Eukaryota

1. Archaea: It is very primitive form of the bacteria.

  they are unicellular, prokaryotic and some are autotrophic and others are heterotrophic.

  The cell walls of Archaea contain no peptidoglycan.

Archaea often live in extreme climate

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.

  Archaea have membranes composed of branched hydrocarbon chains (many also containing rings within the hydrocarbon chains) attached to glycerol by ether linkages.

2.Eubacteria:

Bacteria are prokaryotic cells and are common in human's daily life, we encounter this many more times than archaebacteria. Eubacteria can kill thousands of people each year.

But, It serves as antibiotics and digesters of our food . The Bacteria possess the following characteristics:

1. Bacteria are prokaryotic cells.
2. They have membranes composed of chains of unbranched fatty acid and are attached to glycerol with the help of ester linkages .
3. The cell walls of Bacteria contain peptidoglycan.
4. Bacteria are sensitive to antibacterial antibiotics but are resistant to most antibiotics that affect Eukarya.
5. Bacteria contain rRNA as indicated by the presence molecular regions different from the rRNA of Archaea and Eukarya.

Eukarya (eukaryotes)

The Eukarya possess the following characteristics:

1. Eukarya have eukaryotic cells.
2. They have membranes composed of unbranched fatty acid chains attached to glycerol with the help ofester linkages .
3. Not every Eukarya possess cell wall, but for those Eukarya having a cell wall, the wall contains no peptidoglycan.
4. Eukarya are resistant to antibacterial antibiotics but are sensitive to most antibiotics that affect eukaryotic cells.
5. 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.

Bacteria Archaea Eukaryota Slime Spirochetes Animals Fungi Proteobacteria Green Filamentous bacteria Entamoebae molds Gram Methanosarcina positives Methanobacterium Halophiles Methanococcus T.celer Thermoproteus Pyrodicticum Plants Ciliates Cyanobacter la Plactomyces Flagellates Trichomonads Bacteroides Cytophaga Microsporidia Thеrmоtоga - Diplomonads Agurrex