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Chap 6-7 (Eukaryotic cell (Endomembrane system (Golgi apparatus (Receiving…

- - - - encloses the nuclues
      - double membrane
      - perforated by pore structures
      - nuclear lamina
        
        lines the inside of the nuclear envelope
        
        made of an array of protein filaments (intermediate filaments in animal cells)
      - outer layer is connected to the rough ER
    - - chromosomes- tightly wound DNA- formed during mitosis
      - chromatin- normal state of DNA-- unraveled
      - chromatid- sister chromatids are the duplicated DNA
  - - - bound- attached to rough ER-make proteins headed for insertion into membranes
      - free- loose in the cytosol- makes proteins that function in the cytosol ie enzymes
  - - - smooth ER
        
        no bound ribosomes
        
        makes lipids- oils, steriods, phospholipids etc
        
        detoxify drugs and poisons
      - membranous system of tubuoles and sacs called cisternae--cisternal space or ER lumen is the space inside the membrane
      - rough ER
        
        has bound ribosomes and is connected to the nuclear envelope
        
        bound ribosomes synthesize proteins
        
        can attach carbohydrates to proteins to make glycoproteins
        
        makes membrane and membrane proteins
        
        vesicles bud off of the transitional er
    - - Receiving and shipping center! Sorts the proteins that a cell makes
      - especially extensive in cells that specialize in secretion
      - looks like a stack of pancakes
      - cis face--receiving trans face--shipping
      - does some finishing touches on some products
    - - sac of hydrolytic enzymes used to digest macromolecules
      - carry out intracellular digestion
      - breaks down food (good or bad) or intracellular materials and recycles what can be recycled
      - trash can or recycling bin of the cell
    - - transport vesicles
        
        can bud off the transitional ER and fuse with the Golgi
        
        golgi receives and sends off vesicles containing products destined for all parts of cell
      - sacs made of membrane
    - - food vacuole
        
        formed by phagocytosis
        
        small and found mostly in animals
      - contractile
        
        found in unicellular eukaryotes
        
        pumps excess water out of the cell to maintain the correct concentration of ions in and out of the cell
      - central vacuole
        
        found in plants
        
        collects water
  - - - has double membrane
        
        outer membrane is smooth
        
        inner membrane has lots of infoldings called cristae--lots of surface area
        
        matrix is inside the inner membrane--plasmids and ribosomes found here
      - where cellular respiration takes place
    - - found in plants
      - structure
        
        double membrane
        
        stack of discs called granum
        
        each disk is a thylakoid
        
        stroma- fluid outside the thylakoids-- contains ribosomes and DNA (plasmids)
      - convert light energy to chemical energy
  - - - hollow tube made of dimers
      - largest of the fibers
      - in all eukaryotic cells
      - functions
        
        cell shape and support (girders)
        
        cell motility
        
        cilia and flagella
        
        lots and lots of cilia usually only one or a small number of flagella
        
        cilia moves with a power and recovery stroke--flagella moves with undulating motion like the tail of a fish
        
        a group of microtubules sheathed in an extension of the plasma membrane
        
        9 doublets of microtubules in a ring with 2 microtubules in the center (9+2)---non motile have a 9+0
        
        dyenin proteins connect the microtubules in the outer ring and are responsible for the movement--have "feet" that "walk" along the microtubule
        
        grow out from a centrosome
        
        centrosomes has 2 centrioles
        
        centriole is composed of 9 sets of triplet microtubules arranged in a ring
        
        compression resisting
        
        serve as tracks for organelles to move on
    - - Intertwined strands of actin (actin is a spherical protein)
      - thinnest
      - in all eukaryotic cells
      - functions
        
        cell shape- tension bearing
        
        muscle contraction
        
        cytoplasmic streaming
        
        cell motility (amoeboid movement)
        
        the cleavage furrow in animal cell division
    - - long fibrous proteins coiled into cables (keratin)
      - only in some animals
      - functions
        
        maintenance of cell shape (tension bearing)
        
        anchors the nucleus and some other organelles
        
        make up the nuclear lamina
- - - - NOT membrane bound
      - where DNA is located
- - - - primary cell wall-relatively thin and flexible--outermost
      - middle lamella-like a glue in the middle
      - secondary cell wall--strong and durable--may be several layers--in between plasma membrane and primary wall
  - - - collagen-accounts for 40% of the protein in a body!-strong fibers outside the cell
      - fibronectin-what connects the collagen and proteoglycan to the integrins
      - proteoglycan complex-web of tiny fibers
  - - - perforates the cell wall in plant cells
      - cytosol passes through to connect the internal chemical environments of neighboring cells
    - - plasma membranes are pressed tightly against each other
      - makes skin water tight
      - bound by proteins
    - - function like rivets
      - intermediate filaments anchor the desmosomes
      - attach muscle cells
    - - provide cytoplasmic channels between cells
      - allow for communication between cells
      - lots in heart muscle
- - - - Phase contrast
      - Differential interference constrast
      - Fluorescence
      - confocal- best resolution of these
      - Brightfield (stained and unstained)-what we have in lab
      - does not always kill the specimen
    - - scanning electron microscope- sees in 3D
      - transmission electron microscopy-2D-see a cross section
      - kills the specimen
- - - - penetrate into the hydrophobic interior of the membrane
      - some are transmembrane (all the way through)
    - - not embedded in the bilayer
      - usually loosely bound to the surface of the membrane (often to the surfaces of the integral proteins)
    - - 1-transport
      - 2.Enzymatic activity- the protein itself may be an enzyme
      - 3.Signal transduction-it may be the transmitter for a message from outside the cell to inside if a molecule cannot go inside itself
      - 4.Cell to cell recognition- glycoproteins can act as id tags- if they bind it is a short binding time as opposed to #5
      - Intercellular joining- proteins may hook together (junctions) more long lasting than cell to cell recognition
      - attachment to the extracellular matrix and cytoskeleton--helps maintain cell shape can send messages ECM to microfilaments and vice versa
  - - - diffusion-movement of particles of any substance so that they spread out into the available space
        
        always diffuses down the concentration gradient
        
        osmosis- diffusion of water- water always goes from the hypo to the hyper solution
        
        tonicity- has to do with the concentration of solutes
        
        isotonic- solute concentration is the same
        
        hypertonic- solute concentration is higher
        
        hypotonic- solute concentration is lower
        
        simple diffusion- no assistance needed-- ideal molecule to cross the bilayer would be very small and nonpolar
        
        facilitative diffusion- needs assistance across the membrane
        
        channel protein- tunnel across the membrane that always stays open
        
        ie aquaporin--facilitates the diffusion of water
        
        ie ion channels- allows ions to pass through--many are gated and open or close in response to a stimulus
        
        carrier protein- changes it's shape to help a molecule across
    - - Electrogenic Pump ie- sodium potassium pump-body needs high Na out and high K in the cells
        
        driven by the membrane potential- difference in net charge from in and out of cell--cell is negative compared to the outside of the cell
      - cotransport-active transport of one molecule makes another passively follow
        
        symport-both molecules go in the same direction
        
        antiport- one goes in one direction and makes the other go in the opposite direction
      - bulk transport
        
        exocytosis-exits the cell
        
        endocytosis-bringing in to the cell
        
        phagocytosis-cellular eating- larger molecules are 'grabbed'
        
        pinocytosis- cellular drinking- a pit is made in the membrane- smaller molecules
        
        receptor mediated endocytosis- only specific things are brought in. The 'pit' is covered in receptors
        
        cell knows where to perform endocytosis due to a coat protein