U1AOS1 Transport Flashcards
What is diffusion?
The tendency of molecules to disperse until they are evenly distributed in the available space
Diffusions concentration change
Moves from a place with high concentration to a place with low concentration
Simple diffusion
Small, uncharged and non-polar molecules passing through the PB (no water) and move from high concentration to low concentration
What is the rate of diffusion?
The rate depends on the concentration gradient, or the two different concentrations on each side
Bigger concentration difference
Faster diffusion
How does water cross the PB?
Through the process of osmosis through a semi permeable membrane
What is osmosis?
The PASSIVE net movement of free water molecules from a place of high concentration to a place of low concentration through a semi permeable membrane
Semi permeable membrane
Membrane that will let some things through (water) but not others (glucose- too big)
Passive
Doesn’t require energy
Osmolarity
The total concentration of solutes in a solution
Hypertonic
- High osmolarity
- Gets smaller because water leaves
Hypotonic
- Low osmolarity
- Gets bigger because water enters
Isotonic
- Equal concentration of solutes
- Stays the same because balanced concentrations
How do roots draw up water?
Through osmosis, concentration of water is higher in the soil, so going to move passively into the root
What is facilitated diffusion?
Polar molecules and large ions in water cannot move freely through the membrane due to the hydrophobic tails, can only pass membrane through specific transmembrane proteins
