Diffusion and Osmosis Flashcards
osmosis
the movement of water from an area of high water conc to low water conc across a semi permeable membrane
diffusion
the movement of molecules from an area of high conc to low conc (eg) gases move by diffusion in lungs o2 -> co2
active transport
the movement of molecules using energy
passive transport
the movement of molecules without using energy
permeable
everything in and out
semi permeable
some in and out
eg of some with semi permeable: mitochondria, nucleus
impermeable
nothing in it out
what type of transport is osmosis’s
passive - special type of energy
solvent
a liquid that dissolves other substances
water
solute
a substance that can be dissolved in water
salt sugar
solution
made up of a solute and solvent mixed together
eg: salt water
what happens when an animal cell (blood cell) is placed in a hypotonic soln eg:distilled water
water enters cell by osmosis
cell fills with water and expands
it may burst and die as there’s no wall
this is called haemolysis
hypotonic
high water conc and low solute conc
what happens when an animal cell (blood cell) is placed in a hypertonic soln eg: salty water
water leaves the cell by osmosis
cell shrinks and loses its shape and may die
this is called crenation
hypertonic
low water conc high solute conc
osmoregulagion
the control of the water and salt balance in an organism
multicellular organisms need to monitor the internal environment for water and salt balance
homeostasis
maintains a constant internal environment
eg: salt and water balance
isotonic
any external solution that has the same solute concentration and water concentration compared to body temp
what happens when a plant cell (onion) is placed in a hypotonic skin eg: distilled water
water will move into cell by osmosis
water will pass into vacuoles and cytoplasm
these will swell and will force the cell membrane against the wall
the cel is now stronger and formed due to turgar pressure
cell is said to be turgid
turgor pressure
the pressure of the vacuole and cytoplasm against the cell wall
what happens when a plant cell (onion) is placed in a hypertonic soln eg:salty water
water will move out of the cell by osmosis
cell loses turgor and becomes weaker
cytoplasm shrinks and cell membrane pulls away from cell wall
cell is said to be PLASMOLOYSED and the plant is seen to wilt
osmosis and food preservation - bacteria
bacteria and fungi cause food decay
if they’re placed in very concentrated solns they will lose water by osmosis
This prevents them from growing and causing food decay (eg:) tinned foods, sardines, jam, fruits
osmosis and food preservation - amoeba
single celled organisms like amoeba don’t have a cell wall and need to protect themselves from influx of water
They have a CONTRACTILE VACUOLE which expels excess water from the cell
Example of osmoregulation
example of osmoregulation
contractile vauole in amoeba to prevent influx of water
