AP Bio 2nd Test- Tonicity and Osmoregulation

What is tonicity?

the ability of an extracellular solution to cause a cell to gain or lose water

what does tonicity depend on?

the concentration of solutes that cannot pass through the cell membrane

what are the three solutions cells can be?

isotonic, hypertonic, hypotonic

What is isotonic?

the concentration of solutes is the same inside and outside the cell

what kind of movement do cells immersed in an isotonic solution have?

no net movement of water across the cell membrane

how does water diffuse in isotonic

water diffuses into the cell at the same rate water moves out of the cell

what is hypertonic?

the concentration of nonpenetraring solution is higher outside of the cell

what happens to cells in hypertonic solutions?

cells lose water to there extracellular surroundings

in hypertonic- water will move to tithe extracellular fluid which will cause the cells to _________________

shrivel and die

what is hypotonic?

the concentration of non penetrating solutes is lower outside of the cell

what happens tho a cell in a hypotonic solution?

cells gain water

when the cell will gain water what will happen?

animal cells swell and lyse; plant cells work optimally

Osmoregulation

cells must be able to regulate their solute concentrations and maintain water balance

which environments created osmotic problems for organisms?

hypotonic or hypertonic

what is a necessary adaptation for life in such environments?

osmoregulation

which organelle helps maintain water balance?

cell walls

what happens to a cell in hypotonic solution?

swells until the wall opposes uptake; the cell is now very firm (turgid)

what happens if a plant is in an isotonic solution?

there is no net movement of water into the cell, the cell becomes flaccid (limp) and the plant may wilt

what happens to a plant in a hypertonic environment?

plant cells lose water; eventually, the membrane pulls away from the wall, a usually lethal effect called plasmolysis

What is water potential?

The physical property predicting the direction in which water will flow

what does water potential include?

effects of solute concentration and physical pressure

water will flow from areas of_______________

-high water potential to low water potential

-low solute to areas of high solute concentration

-high pressure to low pressure