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CELLS:

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CELLS:

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    1. 27 Aug. 2012 Cells.ppt 1 CELLS: Cellular Level of Organization

    2. 27 Aug. 2012 Cells.ppt 2 Variety of Cells

    3. 27 Aug. 2012 Cells.ppt 3 Cell Basic structural & functional unit. Lowest level of organization considered alive.

    4. 27 Aug. 2012 Cells.ppt 4 Cells Cell theory All living things are cellular. large, complex, multicellular organisms single-celled protozoa bacteria Activity (metabolism) of whole organism depends on activities of cells. Metabolism of cells depends on their specific subcellular structures. Continuity of life (reproduction) has cellular basis.

    5. 27 Aug. 2012 Cells.ppt 5 Cells Cell theory: All living things are cellular. Challenged in 20th century. Viruses are non-cellular. Exception not important here. Reductionist view of organisms as colonies of cells. Denies importance of phenomena at higher levels.

    6. 27 Aug. 2012 Cells.ppt 6 Cytology Branch of biology concerned with structures and functions of cells.

    7. 27 Aug. 2012 Cells.ppt 7 Cell Components of a cell: Plasma (cell) membrane Cytoplasm Nucleus

    8. 27 Aug. 2012 Cells.ppt 8 Plasma membrane Fluid mosaic model: Fluid mosaic of phospholipid and protein, resembles soap bubble. Phospholipid has polar and non-polar ends. Cell lives in aqueous (polar) environment. Phospholipids spontaneously form bilayer. Polar heads to aqueous internal and external fluids Non-polar tails to inside of membrane

    9. 27 Aug. 2012 Cells.ppt 9 Plasma membrane

    10. 27 Aug. 2012 Cells.ppt 10 Plasma membrane Boundary of cell Separates cytosol from extracellular fluid Regulates exchange Binds cell to other cells tight junction desmosomes gap junctions Supports membrane proteins Integral Peripheral

    11. 27 Aug. 2012 Cells.ppt 11 Functions of membrane proteins Channels, Transporters, and carriers Receptors Enzymes Intercellular joining Cell identity markers Attachment to cytoskeleton and extracellular matrix

    12. 27 Aug. 2012 Cells.ppt 12 Exchange mechanisms Passive Processes Diffusion Facilitated diffusion Osmosis Filtration

    13. Quiz question 2 2. A cells plasma membrane is made of a. Cholesterol and phospholipid b. Glycolipid and protein c. Phospholipid, protein, and cholesterol d. Protein and cholesterol e. Neutral fats and phospholipid 13 27 Aug. 2012 Cells.ppt

    14. 27 Aug. 2012 Cells.ppt 14 Simple diffusion Net movement of substance from region of higher concentration to region of lower concentration.

    15. 27 Aug. 2012 Cells.ppt 15 Diffusion across plasma membrane Depends on permeability of membrane Plasma membrane usually permeable to lipids, lipid-soluble molecules. Depends on concentration gradient.

    16. 27 Aug. 2012 Cells.ppt 16 Facilitated diffusion Depends on concentration gradient. Requires carrier protein. Does NOT use energy

    17. 27 Aug. 2012 Cells.ppt 17 Osmosis 3 defining characteristics Diffusion, of water, through a selectively permeable membrane. Tonicity isotonic hypertonic hypotonic

    18. 27 Aug. 2012 Cells.ppt 18 Filtration Hydrostatic pressure forces water and solutes through a membrane e.g. capillary wall Solutes sorted by size or charge Small ions & molecules pass through Large molecules stopped by filter e.g. making coffee, blood filtered in kidneys

    19. 27 Aug. 2012 Cells.ppt 19 Active exchange mechanisms Active Processes (require, consume energy) Active transport Requires carrier protein Requires energy (ATP) Vesicular (Bulk) transport Exocytosis secretion -- mucus, saliva, digestive enzymes, neurotransmitters, hormones, etc. Endocytosis receptor-mediated endocytosis Phagocytosis

    20. 27 Aug. 2012 Cells.ppt 20 Active transport Requires carrier protein Requires energy (ATP)

    21. 27 Aug. 2012 Cells.ppt 21 Vesicular transport Movement of particles & packages of molecules in vesicles. Exocytosis

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