Exam 4 - Intro to Osmoregulation Flashcards
What is osmoregulation?
regulation of solute concentrations and water balance by a cell or organism
What is a solute?
substance that is dissolved in a solvent to form a solution
What does osmoregulation balance?
the uptake and loss of water and solutes
What changes the stoma size?
changes in turgor pressure that inflate and deflate guard cells
What controls guard cell turgor pressure?
regulation of K+ movement
How does potassium movement relate to guard cell turgor pressure?
- K+ influx increases pressure
- K+ efflux decreases pressure
What is the descending limb of the Loop of Henle permeable to?
water
What is the ascending limb of the Loop of Henle permeable to?
Na+ and Cl-
What creates a solute gradient in the Loop of Henle?
movement of salts out of the ascending limb
What is osmosis?
diffusion of free water across a selectively permeable membrane
What is the water potential equation?
Water Potential = Solute Potential + Pressure Potential
How does water move?
from a system of higher water potential to a system of lower water potential
How are solute potential and solute concentration related?
solute potential decreases with increasing solute concentration
How does water move based on free water concentration and solute concentratino?
- from higher to lower free water concentration
- from lower to higher solute concentration
What drives the movement of water into and out of cells?
osmotic forces
