diffusion and osmosis Flashcards
what is diffusion?
the net movement of particles in a gas or liquid from an area of high concentration to an area of low concentration
what is diffusion a result of?
the random movement of particles
what is the concentration in the plant if it is using up carbon dioxide?
low concentration
explain why carbon dioxide can enter by diffusion?
because there is a lower concentration of it inside the cells
how are leaves adapted to increase the rate of diffusion of carbon dioxide and oxygen?
by having a large surface area
specialised openings called stomata which are spaced out
gaps between the spongy mesophyll cells
how can the rate of diffusion be increased?
having a shorter distance for molecules to travel
a steeper concentration gradient
a greater surface area for molecules to diffuse from, or into
what does osmosis depend on?
the presence of a partially permeable membrane
what does a partially permeable membrane do?
allows the passage of water molecules but not large molecules like glucose
what is osmosis?
the movement of water across a partially permeable membrane from an area area of high water concentration to an area of low water concentration
what is osmosis caused by?
the random movement of water molecules which is not restricted by the partially permeable membrane
why can we predict the net movement of water molecules?
by knowing the different concentrations of water inside and outside cells
what does the entry of water into plant cells increase?
the pressure pushing on cell wall which is rigid and not elastic
what does the turgor pressure do?
supports the cell, stopping it and the whole plant from collapsing
what happens if too much water leaves a cell?
it loses this pressure and the plant wilts
what does turgid mean?
when a plant cell is full of water
