Osmosis Flashcards
Define selectively permeable
only allows certain substances to pass through
Define Diffusion
movement of the molecule from a region of high to low concentration
Define Osmosis
Movement of water molecules from a high water concentration to a low water concentration across a semi-permeable membrane
What is the difference between diffusion and osmosis
osmosis requires a semi permeable membrane where as diffusion doesn’t
What is meant by Turgor?
pressure of the vacuole and cytoplasm against a cell wall of a plant
What appearance does a turgid plant have?
wilts
How does high salt or sugar concentrations help preserve certain foods?
bacteria and fungi have cell walls when placed in a sugar solution they will loose water by osmosis meaning enzymes action will be stopped
What is meant by plasmolysed?
shrinking of the cytoplasm away from the wall of a living cell due to outward osmotic flow of water
Describe how you carried out an experiment for osmosis?
- Soak visking tubing in water
- tie a knot
- fill one with sucrose solution and one with water
- get the mass of the Viking tubing and their solution
- place them in a beaker filled with distilled water
- Leave apparatus for 30 minutes
- remove them from water and get their mass
- Control: stayed the same
- Sucrose visking tube filled with water by osmosis
What is meant by osmoregulation?
the maintenance of constant osmotic pressure in the fluids of an organism by the control of water and salt concentrations.
In which tissue does water travel through plant
xylem
Osmosis has been described as a special case of diffusion. explain why?
Because it requires a semi-permeable membrane
In the case of a named molecule, give precise location at which it diffuses in the human body
oxygen diffuses in alveoli
Give an example of osmosis in plants
plants absorb water from the soil
