membrane transport Flashcards
what is the permeability of molecules through the membrane?
hydrophobic molecules > small uncharged polar molecules > large uncharged molecules > ions
what are the types of transport
simple diffusion
facilitated diffusion via carrier
facilitated diffidino via channel
active transport
what is simple diffusion?
unassisted movement of solute molecules from an area of high concentration to low concentration
what is osmosis?
when the membrane is permeable to solvent but not solutes, solvent moves from an area of low concentration of solute to high concentration of solute
what are the results of a cell being placed in a hypertonic solution
animal –> shrivels
plant –> plasmolyzed
water floods out of cell to balance out high concentration outside of cell
what are the results of cell being placed in a hypoton solution?
animal –> lyse
plant –> turgid
water floods in to balance out high concentration inside of cell
what molecules are able to use simple diffusion?
hydrophobic molecules
- small, non polar
ex gases (CO2)
what is facilitated diffusion
moving down a concentration gradient but requires a transport protein
ex. aquaporin
why is the rate of simple diffusion linear but facilitated diffusion is not?
because simple diffusion does not require the assistance of proteins, and proteins restrict the rate at which molecules can diffuse across
what are the 3 types of carrier proteins
- uniporter –> carries one substance at a time
- symporter –> transports 2 substances going the same direction
- antiporter –> transports 2 substances going opposite ways
what type of carrier protein is GLUT1 and what does it transport
an uniporter –> glucose
what type of carrier protein is anion exchange protein? and what does it transport
an antiporter –> chloride- bicarbonate exchanger
what is a channel protein?
forms a hydrophilic channel that can display a high degree of selectivity
can be selectively opened and closed
diffusion is passive
what is CFTR and what does it do?
allows Cl ions to enter the mucus as well as water to dilute, Na ions flood in to balance out the charge
what happens to CFTR in cystic fibrosis patients
the channels are not functioning properly and Cl ions cannot penetrate the mucus, therefor more prone to infections
