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Chapter 13 - Transport Processes - Coggle Diagram
Chapter 13 - Transport Processes
Concepts
short-distance transport - transport of a few cell diameters or less
Long distance transport - transport between non close cells
Isolation mechanisms - inhibit the movement of substances
Diffusion, Osmosis, and Active Transport
diffusion - random movement of particles in solution cause them to move from areas of high to low concentration
osmosis - diffusion through a membrane
3 types of membranes
Completely impermeable - do not allow anything to pass through. occur as isolation barriers
Differentially/Selectively permeable - only allow certain substances to pass through
all lipid/protein cell membranes are this type
aquaporins - channels for water to enter through
Freely permeable - allow all solutes to diffuse through them
molecular pumps - membrane bound and use atp to force molecules across the membrane
this is known as active transport
Water Potential - the chemical potential of water
Pressure potential - the effect that pressure has on water potential
Pressure increase = potential increase and vice versa
when under tension pressure potential is a negative number
Megapascals (MPa) or bars
osmotic potential - effect of solutes on water potential
matric potential - water's adhesion to nondissolved structures
Short-Distance Intercellular Transport
symplast - protoplasm of an entire plant
apoplast - cell wall and intercellular space combined
Guard cells
open and close of stomatal cells based on short distance intercellular transport
in most plants guard cells are shrunken and have little internal pressure. this closes stomata
when stomata need to open potassium ions are transported to guard cells
this causes water to enter guard cells thus opening the stomata
Motor cells
cells that allow a plant to physically move its leaves
Transfer Cells - cells with great surface area and room for many pumps
Long-Distance Transport: Phloem
pressure flow hypothesis - membrane-bound molecular pumps and active transport are postulated to be the driving forces
sources - where water is transported from
summer and spring - leaves
many species actively transport sugar into sieve elements
Mass transfer - amount of sugar and other nutrients transported by phloem per hour
sinks - sites that receive transported phloem sap
P-protein - functions to seal cut sieve tube elements
Long-Distance Transport: Xylem
Properties of Water
water is cohesive. it interacts strongly with other h20 molecules
water is adhesive. it interacts with many other substances stongly
Water Transport Through Xylem
cohesion-tension hypothesis
transstomatal transpiration - water loss through a plants stomata
transcuticular transpiration - water loss through a plants cuticle directly
cavitation - hydrogen bond is broken in water column
embolism - air space in xylem
