The resistance to antibiotics (Burt & Knight, 2010). This


life contributed aggressively on the earth, despite of the different
circumstances and variety of environment. Microorganisms live everywhere on the
earth, from the deepest places to the highest places. Cells are the constructed
units of all living organisms. Prokaryotes and eukaryotes are the two sort of
living organism beings on the earth (Yamaguchi et al, 2012). Prokaryote is a
cell that does not have a true nucleus and does not have membrane bound
organelles (Yamaguchi et al, 2012). However, Eukaryote has a nucleus and double
membrane bound (Yamaguchi et al, 2012). Prokaryotic cells are smaller and
simpler than eukaryotic cells. It consists of cytoplasm that contains all the
enzymes needed for metabolic reaction, ribosomes, plasma membrane, cell wall
and plasmid which is a small loop of DNA that used to exchange DNA between
bacterial cell that used in genetic engineering, they contain genes giving
resistance to antibiotics (Burt & Knight, 2010). This essay will examine
whether the concept of prokaryotes is valid or fundamentally flowed. 

addition, there are three domains of life on the earth, based on difference of
rRNA gene sequences, Archaea, Bacteria and Eukaryote (Woese& Fox, 1977).

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Woese (1977) claimed that prokaryotes are divided into two groups Archaea and
Bacteria. However, there are many differences between archaea and bacteria.

These include structural difference, and the way they respond to antibiotics,
RNA polymerase and many others (Oren, 2004).


the domain archaea are a heterogeneous group of prokaryotes which vary
particularly from different prokaryotes in their 16S ribosomal RNA arrangements
and in other essential qualities of cell synthesis (Mora & Amann, 2001).

They have the ability to live anywhere in the planet, including the most
extreme environments. They can be found in extreme temperature, extreme PH and
extremely salty environment. The reason of that archaea membrane is made of
ether-containing linkage that is more stable than ester-containing linkage
which presence in bacteria and eukarya, so archaea are able to withstand harsh
conditions (Koga, 2012). In addition to that archaea includes some type of
bacteria halophiles, thermophiles and mathanogens. Halophiles have been found
living in extreme shock conditions like a salt lake and Dead Sea (Olsen et al,
1994). Thermophiles lives in places like thermal vents and hot springs with the
water coming out the earth is near 100o on boiling. These bacteria seem to
build a drive in those conditions the enzymes are specialized for those extreme
temperature conditions (Stetter et al, 1993). Mathanogens live in swamps, mud,
anaerobic environments and produce methane as a waste product. Mathanogens also
found in the remun of cattle and produce methane to digest the cellulose in the
grass. Achaea useful producer of protein in cows (Howland, 2001).  


Mora and Amann (2001) reported that the domain bacteria are various groups of
prokaryotes which vary from the archaea in their 16s ribosomal RNA arrangements
and in other properties that important in forming cell structure. They are the
oldest life forms on the earth, between 3.5 and 3.8 million years old. Bacteria
come in a variety of shapes. These have been established by using Microscope which
has helped identifying bacteria. There are three most common shapes of bacteria
coccus (sphere), bacillus (rods) and spirillum (spiral). The cell wall of
bacteria made of peptidoglycan whereas archaea and eukarya they do not contain
Bacteria are blamed as a cause of human and animals diseases, for instant a
study of cardiovascular medicine at the Cleveland Clinic in Ohio, shows that
bacteria in human gut have to ability to convert nutrients found in meat to
harmful substances that accelerate the build-up of plaques in the arteries
(Woolston, 2013). As a result consuming too much meat especially red meat leads
to increase chance of getting heart disease (Woolston, 2013). Moreover bacteria
cause many other diseases such as Cholera, food poisoning, meningitis,
gastritis and ulcers and other diseases. Not all bacteria are harmful. Likewise
some bacteria lives in the soil a have the ability to breakdown dead organic
matter into simple substance.  Also it
has common used in dairy industry (Hoorman& Islam, 2010).


the domains Eukarya are eukaryotic cells that have nucleus within DNA. Also it
have organelles that do individual jobs such as endoplasmic reticulum,
mitochondria and golgi apparatus.  It
much larger than prokaryotic cells. Eukaryotes have unique rRNA different from
the rRNA of archaea and bacteria. The size of the ribosomal RNA that eukaryotes
have is 80S. Ribosomal RNA consists of two subunit one is large and the other
is smaller. The size of the large subunit is 60S and the size of the small one
is 20S.In addition, eukaryotes are divided into four kingdoms. The first one is
Animalia which composes of a multicellular organism theses includes worms and
insects. The second kingdom is plantae these carry out photosynthesis in
plants. The third kingdom is fungi which do not contain chlorophyll to carry
out photosynthesis. Fungi are heterotrophy, obtaining their nutrients by
absorption. Another fungi are parasitic and obtain their nutrients from other
living organisms. The fourth kingdom is protista which including algea,
protozoans, slime molds and euglenoids.




To sum
up briefly, there are three domains archaea, bacteria and eukarya. These are
living everywhere on the earth. Archaea and bacteria are prokaryotic cells,
that do not have nucleus. Archaea lives in extreme conditions because their
membrane made of ether-containing linkage that is more stable than
ester-containing linkage which presence in bacteria and eukarya. There are
helpful bacteria break down organic matter and harmful bacteria causes disease.

Eukarya domain are eukaryotic cells and more complex than prokaryotes. Eukarya
are divided into four kingdom protista, fungi, plantae and animalia.