Human Phys 1.5 Flashcards
Osmosis
Flow of water across a semipermeable membrane due to a difference in solute concentration
What must be present for osmosis to be possible?
Semipermeable membrane (only always movement of water)
Why does osmosis occur?
Pressure differences (high to low pressure)
How is osmotic pressure determined?
By the number of particles per unit volume in a solution (not by mass)
(The higher the amount the higher the pressure)
What is the importance of osmolarity=gc
Osmolarity= concentration x number of particles
Concentration=50 for NaCl (osmolarity=100)
(But for glucose it = 50 because glucose is one particle)
What is the tonicity of a solution related to?
The effect of the solution on the volume of a cell
Isotonic
Osmolarity is equal so cell does not change
Hypertonic
Osmolarity is higher on the outside of the cell so water leaves cell causing it to shrink
Hypotonic
Osmolarity is lower on the outside of the cell so water rushes in cell causing it to burst
Where does water always move towards?
Higher osmolarity
What does tonicity take into consideration?
The ability of the molecules in solution to cross the cell membrane
Why can osmolarity be equal but tonicity be different?
Example on slide 12 of 1.5
