Lecture #79 & 80

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osmosis
- permeable to water but no solute
- different from diffusion because it has a semipermeable membrane
what is the cytoplasm osmolarity of a regular cell ?

300 m Osmole
what reflection coefficent is completely permeable?

0
water only moves in respone to what?

towards an increased osmotic gradient
what is fick's first law equation
- rate of solute movement is equal to concentration times reflection coefficent
- J=θ* [osmolarity of solute]
simple diffusion characteristics
- linear increase / non saturable
- hydrophobic/ lipophilic
- use no proteins
- no inhibitors
- no substrate selectivity
facilitate transport features
- saturable
- move hydrophilic solutes
- can be active ( use ATP)or facilitated ( w/o ATP)
- use a protein
- specific inhibitors and substrate selectivity
What are the fastest type of facilitate transporters

channel aka pores
active transporters, and diffusive transporter fit under the category of?

Carriers
what some example of facilitated diffusive transporters
- uniporters
- symporter
- antiporters
what are the differences between primary active transport and passive transport
- 1st active
- - uphill or against gradient movement
- - uses ATP
- passive:
- -no ATP
- moves down gradient
how are channels/pores regulated?
- by gating ( different factors that affect open and closed state?
- pore lined with selective binding sites
channel conductance

how much current can pass through a single pore per unit time
how is open probability caculated ?

percent open/percent closed
what is intracellular ligand gating?

GABA or acetylcholine activated gates
what is extracellular ligand gaintg?

Ca or ATpP channels
what molecules control voltage gated

Na+ k+ Cl0 and Ca2+
how do carrier usually transport
- due to a conformational chane
- this can have asymetry carrying capacity based on what surface the the binding site is on
how does the NAK ATPase acrive transport carrier work?
- 3 NA is movin out
- 2 k is moving in
- and 1 ATP is used
why are primary active transporters like Na-K ATPas so useful

They generate a transmemebrane gradient that drive passive transport of other solutes
compared to pores/channel, carrier transport in what speed
- much faster
- >10^6 ions movement /second
characteristic of channels/pores
- only move passively ( down gradient)
- aquesion soltuion filled pore spans the memebrane
gated regulation
basic properties of channels
- open probability
- channel density
- channel conductance
- gating
what kind of carrier moves na and glucose

symporter moving them in the same direction down their gradietn
what allows human to retain water
- different concentration og ions inside versus outside of the cell
- electronegative inside vs. outside
- this is maintained by immobile negavtive chareges of protain
- and NaKAtpase
when calculating the nerst equation you only need to calculate for which ion and why

k because K is the primary ion that cntributes to the resting potential because the otehr ions have very little permeability
what is th nerst equation (simplified)

-61log(concentration inside/conc. outside)=____mV
what are leaks /

when a molecule leaks into the cell via passive diffusion transport
what are pumps

intracellular q levels keep low because active transporter start to move Q out of the cell up/against its gradient
what is net updtake
- more solute is moving in that out
- intracellular concentraionof ion is increasing while extracellular is decreasing
what is equailibrium
- equal transport inside and out of cell
- same amoutn in and out
what is subtrate depletion
- capillay is always releasing intot he interstitum since interstium is off a much large volume
- these compartments never reach equilibrium
alpha intercalated cell function

secrete Ht
B-interclated cells

secrete basic HCo3 secreting

Author

Iana

353384

Card Set

Lecture #79 & 80

Description

membrane transport physiology

Updated

2020-10-07T20:04:17Z

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