L5 - Membrane Transport

Front 1

Diffusion Across Membranes

Back 1

*chemical/electrical gradient
*simple diffusion, channel, carrier
*diffusion - all directions - net diffusion(high to low concen)
*membranes are semi-permeable

Front 2

Diffusion Across Membranes
-hydrophobicity

Back 2

*(things that hate water)
*fat soluble
*fats-fatty acids, cholesterol, steroids
*fats-bound to transport molecules in ECF, ICF, protein, etc.
*gases(O2, CO2) - fluidity - O2 helps transport across membrane easy

Front 3

Diffusion Across Membranes
-size

Back 3

*small objects diffuse across easier then large objects
*H2O, urea->only things small enough to cross
*proteins large and hydrophilic ONLY cross by excocytosi or endocytosis, depending on which way they're going

Front 4

Fick's Law of Diffusion

Back 4

*measures rate of diffusion

Front 5

Ion Channels

Back 5

*Types: Na+, K+, Ca+, Cl=
*both electrical and chemical gradients are important

Front 6

Osmosis

Back 6

*diffusion of water
*move things from high h2o concentration to low h2o concentration
*higher h2o concentration, lower solute concentration.
*lower h2o, higher solute

Front 7

Carrier Transport

Back 7

*carry hydrophilic substances across
*sugars, amino acids, ions
*driven by chemical graients or the use of ATP

Front 8

Carrier Transport
-Specificity

Back 8

*each carrier moves specific molecular type or ion

Front 9

Carrier Transport
-Saturation

Back 9

*limited # of carriers in a membrane
*Tm - transport maxiumum-the fastest rate, when all carriers are used

Front 10

Carrier Transport
-Facilitated Diffusion

Back 10

*no ATP
*chemical gradient which drives them
*molecule binds to carrier, more on high concen. side-movement is to low concen. side

Front 11

Carrier Transport
-Active Transport

Back 11

*(ions)
*use ATP to change carrier affinity(how likely they are to bind) for ion
*movement from low concen. to high concen.
*create ion gradients across membrane

Front 12

Carrier Transport
-Active Transport
-Na-K ATPase

Back 12

*sodium pump
*pumps Na+ out of cell, pumps K+ into cell
*store energy in Na+ and K+ gradients

Front 13

Secondary Active Transport

Back 13

*use Na+ molecules to exchange things
*carrier moves Na+ into cell: sugar/amino acid
*Ion/Ion exchange-> K+/H+, Na+/Ca+ exchanges/cotransported