MS Flashcards
What is diffusion
Diffusion is the net movement of a substance from a region of higher concentration to a region of lower concentration down a concentration gradient
What is net movement
the overall visible movement of particles
When will diffusion stop
Diffusion will continue to occur until the particles are uniformly distributed throughout both sides of the membrane. Concentration is equal in both regions A and B. When that happens, equilibrium has been reached. The dye molecules will continue to move across the membrane at equal rates in both directions. But there is no net movement due to the equal rates of movement
What affects rate of diffusion
Concentration gradient, distance over which diffusion occurs, surface area to volume ratio, size of particles, density of medium in which diffusion occurs, temperature
What is osmosis
Net movement of water molecules from a solution of higher water potential to a solution of lower potential down a water potential gradient through a partially permeable membrane
Region A: 5% sucrose solution
Region B: 20% sucrose solution
Predict what will happen
Region A has a higher water potential than region B. Hence, water molecules from A will move into B by osmosis. Thus, the water level in B increases while the water level in A decreases
What happens to a plant which is watered regularly
firm and upright
What happens to a plant is it has insufficient water
wilt
what is the pressure exerted on a cell wall known as
turgor pressure
