Cellular Structure and Function

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Cellular Structure and Function
2014-02-08 22:09:02
Lecture Notes
Lecture Two, Unit One
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  1. The 3 major regions of a Generalized Cell.
    1.Plasma Membrane: The cells flexible outer surface; isolates cellular content, controls movement in and out of the cell.

    2.Cytoplasm: Contains everything between the plasma membrane and nucleus, mainly the organelles (endoplasmic reticulum, ribosomes, golgi complex, etc.)

    3.Nucleus: Contains cells genetic material which controls the cellular activities; contains nucleolus which contains specific genetic material utilized for ribosome synthesis.
  2. Relate Plasma Membrane structure to Active/Passive transport mechanisms.
    • The plasma membrane is a barrier that consists mainly of lipids and proteins (50/50). -The lipds isolate the cell, the proteins function in transport, communication, control.
    • The membrane is "selectively permeable" (permitted:small, lipid soluble molecules. non-permitted:polar, inorganic molecules).
    • There are channels accross the membrane (regulated and non-regulated) that allow the movement of active and passive substances down the channel.
  3. Passive Transport Processes
    • The movement of materials across a membrane that doesn't require cellular energy. All of the characteristics involve moving from higher to lower concentration.
    • Characteristics that affect the transport are the size/number of transport, lipid solubility, number of carriers present.
    • Simple Diffusion: movement of particles from an area of higher concentration to an area of lower concentration.
    • Osmosis: net diffusion of water through a selectively permeable membrane from an area of higher concentration to an area with a lower one.
    • Facilitated Diffusion: a carrier protein is utilized, same process as simple diffusion.
    • Filtration: water and solutes are forced through a membrane by fluid pressure, moves from higher to lower concentration.
  4. Active Transport Processes
    • Movement of materials across a membrane that does require additional cellular energy (usually in the form of ATP).
    • Vesicular (Bulk) Transport: Movement of larger amounts of materials using a vesicle and cytoplasmic filamentous network and chemical energy; allows movement for large polar molecules and cellular contents in and out of a cell. 
    • Endocytosis: substance may enter a cell.
    • Exocytosis: substance may exit a cell.
  5. Nucleus
    • Consists of nuclear envelope with pores, nucleoli, and chromatin (chromosomes).
    • Contains cellular genetic material which controls the cells activities.
    • Contains specific genetic material utilized for ribosome synthesis.
  6. Cytoplasm
    • Between the plasma membrane and nucleus which holds all of the contents, such as the organelles.
    • Cytosol is the liquid portion, and the organelles are within the cytosol.
  7. Cytoskeleton
    Complex internal structure of the cytoplasm consisting of microfilaments, microtubules, and intermediate filaments.
  8. Microfilaments
    • Inside the cytoskeleton.
    • Plays a role in the function of cellular movement.
  9. Microtubules
    • Inside the cytoskeleton.
    • Holds the cells shape.
    • Coordination in complex cellular movements.
  10. Mitochondria
    • "Powerhouse" of the cell.
    • Site of the most ATP production.
  11. Lysosome
    Membrane-bound sacs containing powerful hydrolytic enzymes for intracellular digestion of enzymes.
  12. Golgi Complex
    • Packaging materials in association with secretion.
    • Sorting and directing of the final cellular products to specific destinations.
    • Synthesis of lipoproteins and glycoproteins.
  13. Endoplasmic Reticulum (ER)
    • Transport and communication between the nucleus and cytoplasm.
    • Acts as a storage site and allows compartementalization of cells.
    • Rough ER: Proteins synthesis.
    • Smooth ER: Lipid synthesis.
  14. Peroxisomes
    • Similar to lysosomes.
    • Contains oxidative enzymes used in detoxification of various materials.
  15. Centrisomes/Centrioles
    • Part of the cytoskeleton.
    • Important in cell division (mitosis and meiosis).
  16. Cilia
    • Part of the cytoskeleton.
    • Moves materials over the surface of the cell.
  17. Flagella
    • Part of the cytoskeleton.
    • Moves the entire cell.