Simple Diffusion Flashcards
Describe simple diffusion
Net movement of molecules from areas of higher concentration to lower concentration
Explain 2 examples of simple diffusion of molecules into/out of cells
1) Gas exchange by diffusion in lung alveoli cells
2) Gas exchange by diffusion through eye cornea cells
Outline factors that regulate the rate of diffusion
1) Concentration of the diffusing molecule (Increase concentration= increase diffusion rate)
2) Temperature (Increase temp, increase diffusion rate)
3) Pressure (Increase pressure, increase diffusion rate)
Describe facilitated diffusion
Still diffusion so:
- Passive (no energy)
- molecules move from high to low
Phospholipid bilayer during facilitated diffusion must be
studded with channel proteins to allow facilitated diffusion to occur
Phospholipid bilayer during simple diffusion must be
permeable to the particle
In the Cell Mem’s case, permeable molecules are usually small and non charged like O2 and CO2)
Describe one example of facilitated diffusion through a protein channel
The CFTR channel moves chloride ions from high concentration inside the cell to areas of low concentration outside the cell
Mutant CFTR Channel
does not move chloride ions, causing sticky mucus to build up on the outside of the cell
Osmosis
The movement of water by diffusion across a membrane (No energy)
Predict the direction of water movement based upon differences in solute concentration
Water moves from hypotonic solutions into hypertonic solutions
Active transport
- requires energy input
- Against concentration gradient (low to high)
Passive transport
- does not require energy input
- With the concentration gradient (high to low)
Explain one example of active transport into and out of cells through protein pumps
Pumps are proteins that actively transport other molecules using ATP as an energy source
EX: protein pump
