Movement in and out of cells Flashcards
What are the main biologically important groups of inorganic molecules?
Respiratory gases
Water
Minerals
Factors affecting rate of diffusion/osmosis
Temperature - particles gain more kinetic energy
Agitating the particles
Surface area to volume ratio - more exposed particles
Difference in concentrations
Distance
Osmosis in plant cells
In pure water/dilute solution: cell gains water and becomes turgid
In concentrated solution: cell loses water and becomes flaccid.
After excessive loss of water: cell becomes plasmolysed
Osmosis in red blood cells
in dilute/hypotonic solution: gains water, swells up and bursts
in concentrated/hypertonic solution: loses water, shrinks and becomes flaccid/crenated
What is osmosis?
Osmosis is the net movement of water molecules from an area of high water potential to an area of lower water potential across a selectively permeable membrane.
Diffusion experiment in a living system
Beetroot cores are dropped into water
Water turns pink when boiling water is added and mixture is stirred
Osmosis experiment in a living system
Potato cores are placed into different concentrations of sucrose solution
After 15 minutes, measure the mass of the potato cores
As you decrease the concentration of sucrose in the solution, the mass change of the potato becomes smaller
Osmosis experiment in a non-living system
Visking tubing filled with a sugar solution is attached to a capillary tube
Water moves from the beaker to inside the visking tubing
What is diffusion?
The movement of particles from an area of higher concentration to an area of lower concentration, down a concentration gradient until equilibrium is reached
What is active transport?
The movement of particles from an area of low to high concentration, against the concentration gradient
Only happens after equilibrium is reached
Requires energy
Equation for respiration in animals
C6H12O6 + O2 -> CO2 + H2O + ATP energy
Equation for respiration/photosynthesis in plants
Carbon dioxide + water -> glucose + oxygen
CO2 + H2O -> C6H12O6 + O2
What does turgid mean?
Swollen, enlarged
Happens in dilute solution when cell has gained water
What does flaccid mean?
Limp, floppy
Happens in concentrated solution when cell has lost water
What does plasmolysed mean?
Cell membrane is pulled away from the cell wall (plant cells only)
Happens due to excessive loss of water
