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Cell biology
The animal cell
Animal Cell.svg
Components of a typical animal cell:
  1. Nucleolus
  2. Nucleus
  3. Ribosome (little dots)
  4. Vesicle
  5. Rough endoplasmic reticulum
  6. Golgi apparatus (or "Golgi body")
  7. Cytoskeleton
  8. Smooth endoplasmic reticulum
  9. Mitochondrion
  10. Vacuole
  11. Cytosol (fluid that contains organelles)
  12. Lysosome
  13. Centrosome
  14. Cell membrane

The cytoplasm comprises cytosol (the gel-like substance enclosed within the cell membrane) – and the organelles – the cell's internal sub-structures. All of the contents of the cells of prokaryote organisms (such as bacteria, which lack a cell nucleus) are contained within the cytoplasm. Within the cells of eukaryote organisms the contents of the cell nucleus are separated from the cytoplasm, and are then called the nucleoplasm. The cytoplasm is about 80% water and usually colorless.[1]

It is within the cytoplasm that most cellular activities occur, such as many metabolic pathways including glycolysis, and processes such as cell division. The inner, granular mass is called the endoplasm and the outer, clear and glassy layer is called the cell cortex or the ectoplasm.

Movement of calcium ions in and out of the cytoplasm is thought to be a signaling activity for metabolic processes.[2]

In plants, movements of the cytoplasm around vacuoles are known as cytoplasmic streaming.

Constituents[edit]

The cytoplasm has three major elements; the cytosol, organelles and inclusions.

Cytosol[edit]

Main article: Cytosol

The cytosol is the portion of the cytoplasm not contained within membrane-bound organelles. Cytosol makes up about 70% of the cell volume and is composed of water, salts and organic molecules.[3]

The cytosol is a complex mixture of cytoskeleton filaments, dissolved molecules, and water that fills much of the volume of a cell. The cytosol also contains the protein filaments that make up the cytoskeleton, as well as soluble proteins and small structures such as ribosomes, proteasomes, and the mysterious vault complexes.[4] The inner, granular and more fluid portion of the cytoplasm is referred to as endoplasm.

Proteins in different cellular compartments and structures tagged with green fluorescent protein

Due to this network of fibres and high concentrations of dissolved macromolecules, such as proteins, an effect called macromolecular crowding occurs and the cytosol does not act as an ideal solution. This crowding effect alters how the components of the cytosol interact with each other.

Organelles[edit]

Main article: Organelles

Organelles (literally "little organs"), are usually membrane-bound, and are structures inside the cell that have specific functions. Some major organelles that are suspended in the cytosol are the mitochondria, the endoplasmic reticulum, the Golgi apparatus, vacuoles, lysosomes, and in plant cells chloroplasts.

Cytoplasmic inclusions[edit]

Main article: Cytoplasmic inclusion

The inclusions are small particles of insoluble substances suspended in the cytosol. A huge range of inclusions exist in different cell types, and range from crystals of calcium oxalate or silicon dioxide in plants,[5][6] to granules of energy-storage materials such as starch,[7] glycogen,[8] or polyhydroxybutyrate.[9] A particularly widespread example are lipid droplets, which are spherical droplets composed of lipids and proteins that are used in both prokaryotes and eukaryotes as a way of storing lipids such as fatty acids and sterols.[10] Lipid droplets make up much of the volume of adipocytes, which are specialized lipid-storage cells, but they are also found in a range of other cell types.

Controversy and research[edit]

The cytoplasm, mitochondria and most organelles are contributions to the cell from the maternal gamete. Contrary to the older information that disregards any notion of the cytoplasm being active, new research has shown it to be in control of movement and flow of nutrients in and out of the cell by "viscoplastic behavior and... a measure of the reciprocal rate of bond breakage within the cytoplasmic network."[11]

See also[edit]

References[edit]

  1. ^ Franklin Institute (November 23, 2013). "Cytoplasm". fi.edu. 
  2. ^ C. Michael Hogan. 2010. Calcium. eds. A.Jorgensen, C. Cleveland. Encyclopedia of Earth. National Council for Science and the Environment.
  3. ^ Cytoplasm Composition. menloschool.org
  4. ^ van Zon A, Mossink MH, Scheper RJ, Sonneveld P, Wiemer EA (September 2003). "The vault complex". Cell. Mol. Life Sci. 60 (9): 1828–37. doi:10.1007/s00018-003-3030-y. PMID 14523546. 
  5. ^ Prychid, Christina J.; Rudall, Paula J. (1999). "Calcium Oxalate Crystals in Monocotyledons: A Review of their Structure and Systematics". Annals of Botany 84 (6): 725. doi:10.1006/anbo.1999.0975. 
  6. ^ Prychid, C. J.; Rudall, P. J.; Gregory, M. (2004). "Systematics and Biology of Silica Bodies in Monocotyledons". The Botanical Review 69 (4): 377–440. doi:10.1663/0006-8101(2004)069[0377:SABOSB]2.0.CO;2. JSTOR 4354467. 
  7. ^ Ball SG, Morell MK (2003). "From bacterial glycogen to starch: understanding the biogenesis of the plant starch granule". Annu Rev Plant Biol 54: 207–33. doi:10.1146/annurev.arplant.54.031902.134927. PMID 14502990. 
  8. ^ Shearer J, Graham TE (April 2002). "New perspectives on the storage and organization of muscle glycogen". Can J Appl Physiol 27 (2): 179–203. doi:10.1139/h02-012. PMID 12179957. 
  9. ^ Anderson AJ, Dawes EA (1 December 1990). "Occurrence, metabolism, metabolic role, and industrial uses of bacterial polyhydroxyalkanoates". Microbiol. Rev. 54 (4): 450–72. PMC 372789. PMID 2087222. 
  10. ^ Murphy DJ (September 2001). "The biogenesis and functions of lipid bodies in animals, growth and microorganisms". Prog. Lipid Res. 40 (5): 325–438. doi:10.1016/S0163-7827(01)00013-3. PMID 11470496. 
  11. ^ Feneberg, Wolfgang; Sackmann, Erich, Westphal, Monika (21). "Dictyostelium cells' cytoplasm as an active viscoplastic body". European Biophysics Journal 30 (4): 284–94. doi:10.1007/s002490100135. PMID 11548131.  Check date values in: |date= (help)

External links[edit]


Original courtesy of Wikipedia: http://en.wikipedia.org/wiki/Cytoplasm — Please support Wikipedia.
This page uses Creative Commons Licensed content from Wikipedia. A portion of the proceeds from advertising on Digplanet goes to supporting Wikipedia.
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78 news items

Phys.Org

Phys.Org
Thu, 30 Oct 2014 06:07:30 -0700

African clawed frog (Xenopus laevis) egg-extract preparation involves collecting unfertilized eggs, crushing them, and separating out fractions of the cytoplasm through centrifugation, a process that divides membranes, organelles and cytoplasm by density.

Phys.Org

Phys.Org
Thu, 30 Oct 2014 05:45:00 -0700

All bacterial cell walls, cell membranes and membranes that separate the nuclei from the cytoplasm have structures that allow one type of molecule to pass through their "doorways" while blocking others, she says. "For example, there is one structure ...
 
Business Wire (press release)
Thu, 30 Oct 2014 06:30:00 -0700

The mechanical stress opens temporary holes in the cell membrane, exposing the cytoplasm, which allows the cell to take up molecules in the surrounding environment. Cells repair themselves shortly thereafter. CellSqueeze technology has been published ...

Medical Xpress

Medical Xpress
Wed, 29 Oct 2014 03:01:46 -0700

Cells with clear cytoplasm are typically arranged in nests. Nuclear atypia is common. Credit: Dr. Bin Teh, Van Andel Research Institute. A new study on a large cohort of kidney cancer patients in Europe sheds light on the genetic architecture of the ...

Mesothelioma.com (blog)

Mesothelioma.com (blog)
Wed, 29 Oct 2014 08:11:15 -0700

... pleural effusion samples showed some or all of the following characteristics: (1) cells containing more than one nucleus; (2) one or two nucleoli in a round or oval nucleus; (3) thick basophilic cytoplasm; (4) stroma of type 2 collagen; (4) hump ...

Guardian Liberty Voice

Guardian Liberty Voice
Wed, 29 Oct 2014 12:31:36 -0700

For example, a mitochondrion produces 36 ATP of energy during cellular respiration but respiration that takes place in the cytoplasm only produces 2 ATP. The Baums' theory suggests that complex life formed from the inside-out. Prokaryotic cells can be ...

Genetic Engineering & Biotechnology News

Genetic Engineering & Biotechnology News
Mon, 27 Oct 2014 21:07:30 -0700

... can easily be detected with a fluorescence microscope. (A) Multiple fluorescent spots in the vicinity of metaphase chromosomes and nuclei indicate the detection of short, human-specific DNA sequences within the mitochondrial genome in the cytoplasm.
 
Nature.com
Mon, 27 Oct 2014 03:58:07 -0700

Since annexin A2 contains an NES sequence and is actively transported to the cytoplasm,29 the amount of nuclear annexin A2 is very low. The minute nuclear annexin A2 protein level was verified by western blotting using the same amounts of whole cell ...
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