Please enable JavaScript.

Coggle requires JavaScript to display documents.

Chapter 12 (Diffusion and active transport # (The three types of membranes…

- - - - Completely impermeable membranes are as the name suggests : essentially brick walls of membranes.
    - - Differentiate and only allow certain substances to pass through.
    - - Does not discriminate and allows all solutes to move past.
  - - - Since it is pumping against resistance, active transport requires the expenditure of ATP.
      - The proton pumps used to push Hydrogen ions across the phospholipid bilayer is a prime example.
      - Pumps against the concentration gradient.
  - - - Migrate through the cytoplasm
        
        Contents are transferred into the organelle
        
        Like the transport of proteins throughout the cell.
        
        Fuse with other organelles
- - - - point of fixation
        
        point may attach to a stem
      - may flec or fold depending on the stimuli present
  - - - potassium ions are continually inserted into the guard cells
        
        since guard cells close upon loss of pressure, they act almost as an automated water loss sensing device, closing to prevent further loss once low pressure is detected.
        
        guard cell walls remain turgid as long as pressure input is continually applied - once this pressure is lost the guard cell will close.
        
        water diffuses in, remembering diffusion is the process of transport through a membrane from an area of high to low
      - use potassium gradient
  - - - allows the inside of the cell to have a larger surface area than if it were flat
        
        allows for a greater volume of cargo to be shipped through
        
        primarily found in places that secrete salts, areas that transport nutrients to areas of new growth, or regions of sucrose in the phloem.
        
        allows room for more transporting tools such as molecular pumps
- - - - transcuticular transpiration
        
        allows some water loss directly through the cuticle itself
      - uses, well, cohesion and tension to operate
      - open stomatal pores allow for the inevitable loss of water
        
        water escapes from cells into the open environment
  - - - water, while moving upwards throughout the tree, also carries nutrients and other materials up with it
      - transpiration prevents the leaves getting too hot, in a way making the tree sweat
  - - - the space between the water molecules draws up other contents
      - molecules are also drawn down from the point of cavitation
      - embolisms are just bubbles of air trapped in a vessel element. while harmful to animals, embolisms are not harmful to plants
- - - - sugar
        
        sieve cells also working
        
        contents flow into conducting cells, but once in cannot diffuse back out, much like a valve in a human vein.
        
        Sieve tubes in use
      - sinks
        
        Callose
        
        injuries can cause pressure loss, such as being crushed or sliced. Once again comparable to a human arterial system.
        
        will eventually coalesce into a precipitate mass.
        
        stays in the solution under pressure
        
        Certain sites are the recipients of phloem sap
    - - places where water and other concoctions are transported throughout the leaf
        
        During the spring and summer the leaves are the dominant sources. But alas, they fall off in the winter.
        
        when the leaves are gone
        
        the parenchyma cells in the wood and bark, like xylem and phloem.
        
        taproots with their massive size and many vascular components
        
        Tubers