细胞质与细胞骨架.ppt

Cytoplasm and Cytoskeleton By:Tim Yacoub and Lizette Magdaleno Cytoskeleton OverviewCytoskeleton is a“network of fibers that extends throughout the cytoplasm,”(113).Its three structures:microtubules,microfilaments,and intermediate filamentsIt helps with the organization of activities,cell mobility,and structure of the cell Cytoskeleton:MicrotubulesIn all eukaryotic cells,Shape:hallow tubesMade from protein called tubulin by centrioles Help shape and support the cell,Compression-resistant,function as roads for mobile organelles to move along.Aid in chromosome separation in cell division.Special arrangement of microtubules form flagella and cilia.Cytoskeleton:MicrofilamentsIn all eukaryotic cells,Shape:thin solid rodsMade from a globular protein:Actin,(twisted double chain of actin subunits).Functions as a tension bearer,networks inside the plasma membrane to support cell shape,this layer is called a cortex.Well known for its aid in cell movement,actin,along with Myosin interact,for example,to contract muscle cells Cytoskeleton:Intermediate FilamentsCoiled cables,larger than microfilaments but smaller than microtubulesMade of several proteins similar to keratinsOnly in some animal cells,bears tension(like microfilaments)More of a permanent structure within the cytoskeleton Reinforces shape of cell,and anchors certain organelles within the cytoplasm Cytoplasm OverviewCytoplasm is“the contents of the cell bounded by the plasma membrane,in eukaryotes,the portion exclusive of the nucleus.”(G-9)Cytoplasm:StructureIt is the Fluid where the cellular organelles are suspended.It fills up all the spaces in the cell that are not being filled by the organelles3 Residents of Cytoplasm:1.Cytosol2.Organelles3.Cytoplasmic InclusionsCytoplasm:CharacteristicsFluid substance that fills the space between the cell membrane and cellular organellesHigh percentage of water It is colloidal It contains proteins90%water and 10%organic and inorganic compounds8Cytoplasm:ZonesPlasmogel-peripheral zone of cytoplasm that is thick and jelly-likePlasmosol-zone is thin and liquefied Cytoplasm:FunctionSite of many biochemical reactionsPlace where cell expands and growsProvides a medium for organelles to remain suspendedAids in movement of different cellular elementsBreak down macromoleculesTransport of genetic material