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Chapter 5B: Cells - Coggle Diagram

- - - - primary: use ATP
      - secondary: uses energy stored in electrochemical gradient
- - - - high to low concentration of water generates force
      - cells maintain HIGH SOLUTE concentration (more solute means less water)
        
        water pushing against gravity to get into cell
        
        very high --> low solute in extracellular space
        
        hypertonic (shrink - water pushing out),
        
        isotonic (normal - water pushing in and out),
        
        hypotonic (swollen - water pushing in),
        
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        multicellular animals maintain isotonic conditions inside and outside cells
      - Use of osmotic pressure
        
        plants use osmotic pressure to maintain shape
        
        bacteria, fungi, plants synthesize polysaccharide cell walls (osmotic pressure)
- - - - cell wall: rigid barrier composed of polysaccharides
      - plastids (chloroplasts): enable plant cells to harness the energy of sunlight to synthesize sugars
      - plasmodesmata: connect neighboring plant cells, allow macromolecules to pass between them
      - vacuole: contribute to the structural rigidity of plants by maintaining turgor pressure against cell walls
    - - nucleus: genetic info, site for RNA synthesis
      - mitochondria: produces most of the ATP (energy for cell)
      - plasma membrane: composed of phospholipids and proteins, regulates passage of materials in/out of cell
      - cytoskeleton: network of proteins that provide cell with internal structure
      - endomembrane system
        
        endoplasmic reticulum: protein/lipid synthesis
        
        secreted proteins and membrane proteins are synthesized right into the ER
        
        when ribosome starts to translate peptide with signal on it that tells cells that it belongs in ER, then ribosome gets attached to ER membrane
        
        proteins in organelles are translated by free ribosomes in the cytoplasm (NOT ER)
        
        "signal sequence" in growing peptide chain sends translating ribosome to channel on surface of ER membrane
        
        lysosomes: degrade macromolecules
        
        golgi apparatus: modifies/sorts proteins and lipids as they move to their final destinations in or out of cell
        
        paroxisomes: break down/synthesizes specific organic molecules
        
        How do proteins get between these "rooms"
        
        "Zipcodes": amino acid sequences specify where they belong
        
        amino acid sequences drive specific localization - have signal sequences
        
        nuclear localization signal: binds to proteins called "Importins"
        
        pulls it into nucleus so nucleus can be active at proper lacolization
        
        Targeting peptide sequence: cleaved-off protein during entry into organelles
        
        "Doors": specialized openings in membranes allow them to pass (nuclear pore complex, channels through the ER membrane for translating proteins)
        
        The nuclear lumen is connected with the cytoplasm by nuclear pores
        
        Nuclear pore complex - regulates passage of larger molecules through nuclear pore (needs active transport)
        
        import proteins from cytoplasm, export RNA to cytoplasm
        
        "In boxes": vesicles can carry them between compartments
        
        Endocytosis: uptake of macromolecules from outside cell