Endomembrane System and Cytoskeleton Vocab Notes
Essay by adri17 • April 13, 2016 • Course Note • 553 Words (3 Pages) • 1,299 Views
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- Endomembrane System and cytoskeleton
- Membrane: A pliable sheet-like structure acting as a boundary, lining, or partition in an organism
- Always enclose a space (cisterna or vesicle)
- Never open ended unless damaged
- Biological membranes move from T-junctions
- Consistency of olive oil in water, therefore no stiff barriers
- Endomembrane System: System of compartments that generally includes all of the membrane-bound components of the cell (including the nuclear envelope) except for the mitochondria and chloroplast
- Cisternae: Flattened, fluid filled tubules within the cell
- Endoplasmic Reticulum: Network of membranous sacs extending throughout the cytoplasm of a eukaryotic cell (usually flat and sheet like but can be linked by tubular cisternae). Rough ER → Smooth ER
- Membrane cisternae that ramify through the cytoplasm. The result is internal compartments and channels
- Provides surfaces for the synthesis of proteins, lipids and carbohydrates.
- Connected to nuclear envelope
- Rough ER: Endoplasmic reticulum with attached ribosomes and involved the synthesis of proteins to be exported from a cell
- Smooth ER: Lacks attached ribosomes
- Golgi Apparatus: Stacks of four to ten disc shaped cisternae functioning in the synthesis of polysaccharides, glycosylation of proteins and the sorting of molecules for storage or secretion
- Golgi Stacks: functional extensions of the ER and are polar structures
- All the polysaccharide in cells is manufactured within the Golgi apparatus
- Polysaccharide may be attached to either protein or lipid molecules in the golgi stacks
- Functions in the collection, packaging, and distribution of molecules synthesized elsewhere in the cell
- Lysosomes: Membrane-bound component of a cell containing hydrolytic enzymes involved in the breakdown and recycling of many types of molecules → attached to the golgi apparatus
- Single membrane bound
- Autophagy: A process where cellular material becomes enclosed in a double membrane and degraded (macromolecules broken down into protein, carbohydrate, lipid and nucleic acid)
- Acidic interior containing specialized enzymes
- Microbodies: Main organelles for removing compounds generated within the cell
- Surrounded by one membrane
- Neutral pH: contain oxidative enzymes that generate hydrogen peroxide and the enzyme catalase to break down the hydrogen peroxide
- Spherical in shape and contains crystalline inclusions
- Peroxisomes: Type of microbody contains enzymes and is involved in the production and degradation of peroxides and oxidation of amino acids and uric acid
- Glycoxysomes: Contains 5 enzymes and is involved in the conversion of fatty acids into sugars
- Plant Vacuoles: Plant version of lysosomes
- Tonoplast: single membrane
- Contains hydrolytic enzymes and serves as degradative compartments
- Storage of nutrients, pigments and maintenance of cell turgor pressure
- Cytoskeleton: Network of microtubules, microfilaments (actin) and intermediate filaments (eukaryotic cell)
- Act as a form of scaffolding or as structural elements within the cytoplasm of cells, and are associated with maintaining cell shape
- Movement of organelles within the cytoplasm and cell movement
- Composed of PROTEIN not membrane
- Microtubule: Hollow protein filament composed of tubulin proteins (tubulin sub units)
- Actin Filament: Globular protein (actin sub units)
- Form stiff structures that do not branch or contract
- Polymerize and depolymerize to satisfy the cells needs
- Polar and highly dynamic structures
- Intermediate filament: Provides mechanical support to the cell. Intermediate in size between microtubules and microfilaments
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