Cytoskeleton+and+Cytoplasm



=**__ Cytoplasm & Cytoskeleton __**  =
 * **__Cytoplasm__** - the jellylike material outside the cell nucleus in which the organelles are located. Technically, the **cytoplasm** refers to both the cellular fluid and the organelles it contains, whereas the **cytosol** refers merely to the fluid. The cytosol is 80% water, but it contains a wide variety of organic and inorganic macromolecules such as proteins, lipids, carbohydrates, and vitamins. These provide nutrients for the cell. The cytosol also contains thousands of enzymes that are responsible for cell processes such as glycolysis (the breakdown of glucose), and the biosynthesis of fatty acids, sugars, and amino acids. The cytosol is rich in salts and is a good conductor of electricity, which helps drive the mechanics of the cell. The cytoplasm helps facilitate the movement of organelles around the cell by moving and churning in a process called **cytoplasmic streaming.**




 * __**Cytoskeleton**__ - the internal network of protein filaments and microtubules in eukaryotic cells that are responsible for controlling the cell's movement, establishing the shape of the cell, providing mechanical strength, chromosome transportation during cell division, and the intracellular transport of organelles. The cytoskeleton is made up of three types of protein filaments: **actin filaments** (also called **microfilaments**), **intermediate filaments**, and **microtubules**.

- responsible for muscle contraction - carry out cellular movements including gliding, contraction, and cytokinesis - generates cytoplasmic streaming in some cells || - provide a supporting framework of tensile (tension) strength for the cell. || - determine cell shape and are responsible for most cell functions involving motion - motion is driven by microtubule "motors" that run on ATP - kinesin motors move towards the "plus" (active) end, while dyenin motors move towards the "minus" (inactive) end ||   **Links:** Cell model:  http://www.cellsalive.com/cells/cell_model.htm    > Videos on the cytoplasm & cytoskeleton  :   http://www.howstuffworks.com/search.php?terms=cytoplasm&media=video Quiz on the cytoskeleton: http://library.thinkquest.org/27819/cgi-bin/quiz.cgi?quiz=3_7 Video on cytoplasmic streaming: http://www.cells.de/cellseng/1medienarchiv/Zellfunktionen/Motilitaet/Plasmabewegung/Algen_u_Wurzelhaarspitzen/index.jsp
 * __ **Cytoskeleton ** __ || **__Description__ __&__ __Function__**  ||
 * < [[image:cytoskeleton.gif width="409" height="76" link="http://library.thinkquest.org/C004535/cytoskeleton.html"]] ||< - composed of a contractile protein called actin
 * < [[image:intermediate_filaments.GIF width="403" height="78" link="http://library.thinkquest.org/C004535/cytoskeleton.html"]] ||< - several different types with varying functions (ex: lamins stabilize the nuclear envelope, neurofilaments support neurons, vimentins provide mechanical strength to muscle cells)
 * < [[image:microtubules.GIF width="389" height="81" link="http://library.thinkquest.org/C004535/cytoskeleton.html"]] ||< <span style="COLOR: rgb(144,63,151)">- composed of subunits of the protein tubulin

**Sources:** Evan and Melanie. "Cytoplasm." 27 Oct 2008  http://sln.fi.edu/qa97/biology/cells/cell3.html "What is cytoplasm?." __Essortment__. 27 Oct 2008   http://www.essortment.com/all/cytoplasm_rkkg.htm "The Cytoskeleton." 27 Oct 2008 http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/C/Cytoskeleton.html <span style="DISPLAY: block; COLOR: rgb(3,2,2); TEXT-ALIGN: left">"Cytoskeleton Tutorial." __The Biology Project__. 27 Oct 2008 http://www.biology.arizona.edu/Cell_BIO/tutorials/cytoskeleton/page1.html "Journey into the Cell: The Cytoskeleton." __About.com: Biology__. 27 Oct 2008 http://biology.about.com/od/cellanatomy/a/aa013108a.htm