Water Flashcards
(11 cards)
Properties of water
Polar acts as solvent so metabolic reactions can happen faster in solution
Important for hydrolysis and condensation reactions
Comparison between water and ions
Both move down concentration gradient
Both move through protein channel in membrane
Ions can move against conc gradient through active transport
What’s a xylem
Hollow tubes that transport water
What’s transpiration
Water evaporates out of stomata on leaves of plant- helps transport materials in plant
What’s cohesion tension theory
It explains the tension caused by loss of water at the top (stomata) and water moving in at the bottom (root pressure)
Lower water potential in mesophyll
Water pulled up xylem
Water molecules cohere to one another by hydrogen bonds
Adhesion of water to walls of xylem
How do xerophytes reduce water loss
Thick cuticle
Rolled up leaves traps air becomes moist and reduces the water potential gradient
Hairy leaves for same reason
Smaller surface area to volume ratio
Evidence for cohesion tension theory
Tree trunks have wider diameter at night when transpiration is at its lowest so least tension
What’s the phloem
Tissue that transports the biological molecules in either direction made of sieve tube elements arranged end to end. Walls perforated to form sieve plates. Companion cells often associated with sieve tube elements
What’s translocation
How organic molecules and mineral ions are transported around the plant
What are plant sources and sinks
Source is where sugars are made from photosynthesis and sinks are where they’re stored
What’s the mass flow hypothesis
Sugars in the source are actively transported into her phloem by companion cells
Lowers water potential of sieve cell/tube and water enters by osmosis
Increase in pressure causes mass movement
Sugars used and converter in the root
