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2 Cards in this Set
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4. Describe or draw and label the components of the Fluid Mosaic Model of a plasma membrane.
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Basic material is a Phospholipid Bilayer surrounded by extracellular fluid (top) and intracellular fluid (bottom)
Hydrophillic (polar) "heads" form outer and inner surface. Attracted to water in intracellular & extracellular fulids hydrophillic heads sugar polar Hydrophobic (nonpolar) tails form membrane interior. Attracted to themselves hydrophobic tails fatty acid nonpolar The tendency of bilayered phospholipids to self-roient encourages self-assembly into spherical forms that self-repair Glycolipid molecules with attached sugars constitute about 5% of plasma membrane lipids. Sugar groups are polar; fatty acid tails are nonpolar Cholestoral constitutes about 20% of membrane lipids. Flat shap stabilizes phospholipid tails and makes the membrane less fluid Proteins "floating" in this bilayer form mosaic pattern. They constitute 20% of plasma membrane materisl and their functions are: transport, enzyme, receptor, intercellular joining, recognition & cytoskeletal Integral Proteins - integrated into lipid bilayer; most are transmembrane, extending through both membrane surfaces with both polar and nonpolar portions; primarily involved in transport (channels, carriers, receptors) Peripheral Proteins - not embeded in lipid bilayer but loosely attached to integral proteins or lipids; On both inner and outer membrane surfaces; includes intracellular network of filaments attached to components of the cytoskeleton Glycocalyx - composed of branched glycoproteins and glycolipids on external plasma membrane surface Different cerll types have different sugars and arrangements of sugars in their glycocalyx. Important in recognition (e.g. sperm/egg, immune response, cancer immunology |
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1. State and discuss the modern interpretation of the Cell Theory
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Cells are the structural and functional units of living things
1) Activities of organisms depend upon individual and collective cellular activities 2) Cellular activities result from the pesence and abundance of organelles i.e. principle of complementarity: biochemical activities of cells are dictated by the relative number of their specific subcellular structures 3) The continuity of life has a cellular basis |
