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Chapter 13: Transport processes - Coggle Diagram
Chapter 13: Transport processes
Concept
Transport process
Short distance transport: involve a transport between few distance and less
long distance transport: transport between cell that are not close
epidermis: helps to keep water in the shoot after it has been transported there by the xylem.
casparian strips: prevent diffusion of the minerals from one part of root to another.
Diffusion, osmosis and active transport
Diffusion: random movement of particles in solution cause them to move from the area of high concentrataion to low concentration.
Osmosis: diffusion through osmosis
Type of membrane:
freely permeable: allows all solutes to diffuse through them.
completely permeable: membrane do not allow anything to pass through.
selectively permeable: allow only certain substances to pass
Aquaporin: protein that make the movement of water molecule more rapidly.
Molecular pump: use ATP to force molecule across the membrane.
intracellular transport:: vesicle migrate through the cytoplasm and fuse with another organelle.
Water potential
Chemical potential of plant
Pressure potential: the effect that pressure has on water potential.
If water is under pressire, pressure potential and water potential increases.
Unite of potential: megapascals or bar
osmotic potential: the effect that solute have on water potential.
matric potential: Amount of water bound to the matrix of a plant via hydrogen bounds and is always negative to zero.
cells and movement
Lysis: The process of bursting animal cells when placed in pure water.
Eutrophication: process by which a body of water becomes progressively enriched with minerals and nutrients.
Plasmolyze: cell become plasmolysis when it constantly lose water to the atmosphere.
incipient plasmolysis : the point at which protoplast has lost enough water to pull slightly away from the wall.
Short distance intracellular travel
Guard cell
surrounded by stomatal pore located at leaf epidermis
control influx and efflux of CO2 and water from leaves.
At night
Stomata close
guard cell shrunken
little internal pressure
Hydraulic equilibrium with surrounding cells
water enter and leave guard cell with same amount so no net change occurs.
At day
Stomata open
potassium ion are transported from surrounding cells into guard cells
hydraulic equilibrium by potassium pumping and water diffusion out of the surrounding cell
Motor cell
Large bubble-shaped epidermal cells
occurs in the groups of upper surface of the leaves of many monocots.
Make the leaves curl during the water stress to reduce the loss of water due to evaporation
Transfer cell
Wall are smooth but have numerous gingerlike and ridgelike outgrowth on the inner surface.
specilized parenchyma cell have increased surface area
Faciliate the transport of sugars from the sugar source, mainly mature leaves
Symplast: All of the protoplasm of one cell can be considered one continuous mass called symplast.
Apoplast: space outside the plasma membrane within ehich materials can diffuse freely.
Long distance transport : Pholem
Pressure flow hypothesis
best supported theory to explain the movement of sap through the pholem
sources: site through which water and nutrient are transported
With in the source of many species, sugar are actively transported into sieve elements
polymerase trape mechanism
sucrose is transfered into heavier sugars, such as raffinose and stachyose in the intermediatary type companion cells bordering the sieve elements in the minor veins of the pholem
conducting cell plasma membrane is permeable to monosaccharide and disaccharides but not to polysaccharides
STM/CC complex
functional unit constiting of a conducting cell and one or several companion cells
Mass transfer
the actual amount of sugar and other nutrients transported by pholem per hours
specific mass transfer: mass transfer through the cross section of pholem to make comparison easier
Sinks
sites to receive transported pholem sap and extremely diverse
Long distance transport: Xylem
Properties of water
Cohesive
any force acting on one molecule acts acts all neighboring as well
Adhesive
Molecule of water interact with many other substances
Almost all substance in plant except lipid interact with water
Water transport through xylem
Cohesion tension hypothesis
Most widely accepted theory
Cohesion cause more water molecules to fill in the gap in xylem as the top-water is pulled towards the stomata
Transtomatal transpiration: Water loss at 50%relative humidity where warm air can have water potential as negative as -50.00 MPa
Transcuticular transpiration
Water loss through cuticle during transpiration
control of water transport by guard cell
Guard cell use osmotic pressure to open and close stomata, allowing plants to regulate the amount of water and solute within them.
If leaf has an adequent moisture content, light and carbon dioxide are the normal controlling factors.
