There are three main divisions of living organisms: Prokaryotes, eukaryotes and archaea. This essay will outline the division between the prokaryotic and eukaryotic organisms and explore the reasoning behind such differences with regard to general structure, storage of deoxyribonucleic acid (DNA) and its replication, metabolic processes, protein synthesis and ribonucleic acid (RNA) processing.
The cell is the most basic unit of life, defined as “The fundamental ... structural and functional unit of all living organisms” (Oxford University Press, 2008). The prokaryotic cell is typically composed of a plasma membrane and cell wall, containing within it the cytosol and a structure known as the nucleoid. This is a single piece of circular or linear DNA that floats freely in the cytosol of the cell (Thanbichler and Wang et al., 2005, pp. 507). In contrast, eukaryotic organisms typically include (but are not limited to) membrane-bound organelles such as the nucleus, mitochondria, endoplasmic reticulum (E.R.), golgi body, lysosome and peroxisome. The main defining difference between a eukaryote and prokaryote is that the latter does not contain a nucleus or any such organelles. Such a definition, however, can be argued to be a poor discriminator between organisms of Eukarya and Prokarya, because it describes only what prokaryotes are lacking, not what they fundamentally ‘are’. This essay aims to detail a more comprehensive definition of why these two kingdoms are so different from each other. A key example of this thinking is that, while prokaryotes are often single responsibly for metabolic processes, reproduction and cell repair, eukaryotes are often highly specialised to perform certain functions and rely upon other cells to fulfil ...
... middle of paper ...
...icrobiology and molecular biology reviews, 69 (2), pp. 292--305.
Shapiro, J. 1998. Thinking about bacterial populations as multicellular organisms. Annual Reviews in Microbiology, 52 (1), pp. 81--104.
Stryer, L. 2012. Biochemistry. 7th ed. New York: W.H. Freeman.
Thanbichler, M., Wang, S. and Shapiro, L. 2005. The bacterial nucleoid: a highly organized and dynamic structure. Journal of cellular biochemistry, 96 (3), pp. 506--521.
Van Der Oost, J. and Brouns, S. 2009. RNAi: prokaryotes get in on the act. Cell, 139 (5), pp. 863--865.
Woese, C. and Gogarten, J. 1999. When did eukaryotic cells (cells with nuclei and other internal organelles) first evolve? What do we know about how they evolved from earlier life-forms?.Scientific American, [online] 21st Oct. Available at: http://www.scientificamerican.com/article.cfm?id=when-did-eukaryotic-cells [Accessed: 22 Oct 2013].
There are many different cells that do many different things. But all of these cells fall into two categories: prokaryotic and eukaryotic cells. Eukaryotic cells contain a nucleus and are larger in size than prokaryotic cells. Prokaryotic cells do not contain a nucleus, are smaller and simpler than eukaryotic cells. Two of their similarities are they both have DNA as their genetic material and are covered by a cell membrane. Two main differences between these two cells are age and structure. It is believed that prokaryotic cells were the first forms on earth. They are considered primitive and originated approximately 3.5 billion years ago. Eukaryotic cells have only been around for about a billion years. There is strong evidence that suggests eukaryotic cells may be evolved from groups of prokaryotic cells that became interdependent on each other (Phenotypic analysis. (n.d.).
Miller, Kenneth R. and Joseph S. Levine. “Chapter 12: DNA and RNA.” Biology. Upper Saddle River: Pearson Education, Inc., 2002. Print.
Eukaryotic Cells are Deemed as a Result of the Evolution of Symbiotic Prokaryotes Both Prokaryotic and Eukaryotic cells over time have sustained very dynamic changes from one another. More specifically we have seen the appearance of a more complicated and organized cell structure, the nucleus. However the big question amongst scientists today is how did these changes first occur? A fundamental concept of this evolution is the belief in the natural progression 'from the simple, to the more complex.' However one popular theory that argues that Prokaryotic symbiosis was responsible for forming the Eukaryotic nucleus is the 'Endosymbiotic Theory' this theory was first proposed by a former Boston University Biologist known as Lynn Margulis in the 1960's.
Hall, Linley Erin. “Understanding Genetics DNA and RNA.” New York: The Rosen Publishing Group, Inc., 2011. Print. 01 Apr. 2014.
West-Eberhard, M.J. 1998. Evolution in the light of developmental and cell biology, and vice versa. PNAS, 95: 8417-8419.
Gardiner, L. (2004). Organelles of Eukaryotic Cells. In Windows to The Universe. Retrieved December 8, 2013, from http://www.windows2universe.org/earth/Life/cell_organelles.html.
Talaro , K., & Chess, B. (2012). Foundations in microbiology. (8th ed., pp. 563-564). New York, NY:
Trafton, A. (2013, June 23). MIT News. Enhancing RNA Interference, pp. 1-2. Retrieved 12 16, 2013, from http://web.mit.edu/newsoffice/2013/enhancing-rna-interference-0623.html
The start of any evolutionary story told about us lies within the origin of the eukaryote cell. This remarkable event consisted of a revolution of cell type matched in momentousness by the arrival on the biological scene of the prokaryote (O’Malley). Bacteria had a couple billion years head start on eukaryotes and have given rise to many biochemical processes that are essential to the ecosystem (Wernergreen). One organism living within another defines endosymbiosis. Nobody can say the exact origin of the eukaryote cell. The endosymbiosis theory dates back to the earliest 20th century and devotion to different models of its origins is strong and adamant (O’Malley).
The nucleus is one of the most important organelles in a eukaryotic cell. The shape of the nucleus is generally spherical, it should be oval, disc formed reckoning on the sort of cell. The nucleus was found by Robert Brown in 1831 while he was looking at orchids under a microscope. He discovered a blurred area in the cells of the flowers and called it the areola or the nucleus.
...ed on the fact that all organisms are made up of the same four nitrogenous bases combining to form nucleotides. From the simplest of bacteria millions of years ago, to the most complex structures and systems found in mammals today, all organisms are comprised of the same nucleotides, merely arranged differently. These nucleotides, which form the genetic code, are transferred from one generation to the next through DNA in either asexual or sexual reproduction. Over millions of years of evolution and adapting to ever changing environments, organisms continue to pass down hereditary information to their offspring (Steitz undated). This is proof of an ancestral link between all organisms that live on earth today, as well as those which have perished to extinction. Thus the continuity of life is preserved through the passing of heritable information in the form of DNA.
In the most general terms, the nucleus is the command center of a eukaryotic cell. Although the origin of the organelle is unclear, it is believed that it is derived from a symbiosis relationship between a bacterium and an archaea (Martin W. 2005). Being the main hub for the inner workings of a cell involves different functions overall. These nucleic functions are determined by the genes within the DNA of the cell. Functions of the cell are also regulate by soluble proteins that come in and out of the cell via the membranes and specific channels or the nuclear pore complexes. The overall objectives of the nucleus include; gene expression, compartmentalization, and processing pre-mRNA. The functions of the organelles and sub-regions
Bacteria are single celled microbes. Bacteria reproduce by binary fission. In this process, the bacterium, which is a single cell, divides into two identical daughter cells. Binary
The membrane surrounding the nucleus in eukaryotic cells, separate the nucleus from the cytoplasm. Most of the cells we used in the experiments held, were multicellular or consisting of more than one cell. A variety of cells were used in completing the experiments. We used union cells, cheek cells, potato cells, and Elodeo cells. We also used Planaria which is a unicellular organism.
Prokaryotic cell: have no membrane covered organelles, they also have circular DNA and bacteria, Eukaryotic cell: have membrane covered organelles, they also have linear DNA and all other cells. Also the cell cycle is short in prokaryotic cells, roughly taking about 20-26 minutes to complete. And in eukaryotic cells, the cell cycle is long, it usually takes about 12-24 hours to complete. Below is a table of some of the differences between the cells: