Eukaryotic cell

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The word 'Eukaryotic'' means 'true nucleus' and eukaryotic cells have. Eukaryotic cellsonly contain organelles that are distinctly membrane-bound such as nuclei, mitochondria and chloroplasts (plants only). Animals, Plants, Fungi and Protoctista are all eukaryotes; bacteria are prokaryotes. In comparison, eukaryotic cells are larger than prokaryotic cells with a diameters ranging from 10-100 μm. Organisms with eukaryotic cells are referred to as eukaryotes. There are two types of eukaryotic cells; animal and plant cells, which are distinguishable in terms of their ultrastrctures[1].

A eukaryotic cell is a cell that has its DNA in a distinct compartment from the cytoplasm of the cell due to a membrane; DNA is inside a nucleus. They also have a cytoskeleton that holds the cell's shape, gives it mechanical strength and helps to move things around the cell. Eukaryotic cells have membrane bound organelles such as the endoplasmic reticulum, Golgi apparatus and mitochondria. Eukaryotic cells are typically much larger than prokaryotic cells. Animal cells are an example of eukaryotic cells[2].  

Eukaryotic cells are any cell with a membrane bound nucleus. The term 'Eukaryote' comes from the the greek meaning trully nuclear[3]. Eukaryotes include animal and plant cells. These tend to be highly specialised for function within large multicellular organisms (e.g. Mammals)

Eukaryotic cells contain many compartments, known as organelles. These organelles are membrane bound, allowing segregation of activities.

The main organelles are:

Different Structures

The two main types of eukaryotic cell are the animal cell and plant cell, between which there are a few differences.

Animal cells have a plasma cell membrane inside of this are all the organelles and cytosol. There is the nucleus which contains the genome enclosed in the nuclear envelope. This is surrounded by the endoplasmic reticulum which can have ribosomes attached. Surrounding this are the organelles as follows: the Golgi Apparatus, free Ribosomes, Lysosomes, Peroxisomes, Centrosome and Mitochondria. Other structures within the cell include Vesicles, Actin Filaments, Microtubules and Intermediate Filaments[5].

Plant cells are different in that they have a Cellulose Cell Wall as well as a Cell Membrane and large Vacuoles. Other differences include Choroplasts instead of Mitochondria, Plastids for storage, and not having Peroxisomes [6].

Ultrastructure

To be classed as a eukaryotic cell, the cell must contain a nucleus, with genetic material, surrounded by a double membrane (or envelope) and organelles (structures) in the cytosol, each surrounded by one or two membranes also. The organelles include; the nucleus which contains the main genome and is the site of  DNA synthesis and RNA synthesis, the endoplasmic reticulum which is the site of synthesis for most lipids and proteins and is responsible for the distributution of these molecules to many organelles and to the plasma membrane, the Golgi apparatus is responsible for the modification, sorting and packaging of proteins and lipids for either secretion or delivery, lysosomes which are used for intracellular degradation, endosomes which are responsible for endocytosed material, mitochondria which are required for oxidative phosphorylation and peroxisomes which are responsible for the oxidation of toxic molecules. In plant cells, an addition number of organelles are present such as chroloplasts which are essential photosynthesis instead of mitochondria but also do not contain organelles such as peroxisomes[7]

For more detailed and illustrated information visit : thecellorganelles.weebly.com/index.html

References

  1. Alberts, B., Johnson, A., & Walter, P. (2007). Molecular Biology of the Cell. United States: Garland Publishing Inc. pp. 26-27
  2. Alberts, Johnson, Lewis, Raff, Roberts and Walter. (2008) Molecular Biology of the Cell. 5th edition, New York: Garland Science (pp26-27)
  3. http://library.thinkquest.org/C004535/eukaryotic_cells.html ; Accessed on 24/11/2010
  4. B Alberts, A Johnson, J Lewis, D Morgan, M Raff, K Roberts, P Walter. Molecular Biology of the Cell. 6th Ed. New York: Garland Science. 2014.
  5. Watson J D, Gilman M, Witkowski J and Zoller M (1992) Recombinant DNA, 2nd Edition, New York: W H Freeman and Company (Chapter 6)fckLRBerg J M, Tymoczko J L and Stryer L (2007) Biochemistry, 6th edition, New York: W H Freeman and Company (P140-142)
  6. Pearson NCS (2014), Plant Cell, Available at http://biology.tutorvista. com/animal-and-plant-cells/plant-cell.html (Last Accessed 27/11/2014)
  7. Hardin, J., Bertoni, G., & Kleinsmith, L. (2012). Becker's World of the Cell. United States: Pearson Education (US). pp.75-105

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