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Unformatted text preview: Chapter 3 Cells: The Living Units
Bonnie S. Gunn Lecturer UTPA Cell Theory Cell is the structural and functional unit of organisms Activity of an organism is dependent on cellular activity (individually and collectively) Biochemical activity is related to the subcellular structures (organelles) Continuity of life has a cellular basis Generalized (Composite) Cell 3 main parts Plasma membrane Cytoplasm Barrier, outer boundary Semifluid medium Contains organelles Small structures that perform specific cellular functions Controls cellular activity Contains DNA Usually near the center of the cell Nucleus Structure of generalized cell Plasma Membrane: Structure Plasma membrane structure Fluidmosaic model
Lipid bilayer construction Integral proteins Receptors Functions of membrane proteins Functions of Membrane Proteins: Transport Enzyme activity Receptors Intercellular recognition Cell joining o Tight junctions o Desmosome o Gap Junction Functions of membrane proteins Cell junctions Cell junctions Cell junctions Diffusion Molecules move from areas of high concentration to that of low concentration Move along a concentration gradient Simple Facilitated Osmosis (movement of solvent) Solutions Hypertonic: More concentrated Hypotonic: More dilute Diffusion through the plasma membrane Diffusion through the plasma membrane Diffusion through the plasma membrane Diffusio...
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