electrochemical gradients

explain movement of particles in diffusion

• overtime conc gradient becomes dissipated

• molecules move spontaneously

  • due to increase in entropy

why do ions spread out

• constant thermal agitation

• go short distance before bumping into one another

einstein’s take on diffusion

• depends how many dimensions molecules move in

• move faster and further in 3 dimensions

  • less chance of bumping into one another

which molecules move in 1 dimension

• movement of transcription factors

where is there movement in 2d

membrane

where is there a movement in 3d

lipids

why catalysts work in terms of dimensions

• enzymes provide 2d surface

• allows molecules to bump into one another

signaling molecules and dimensions

• molecules in membranes have more chance of interacting 2d - g protein coupled receptors

• longer ranges if not bound to membranes 3d

electrophoretic movement of ions

movement of ions under the influence of electrical field

electrochemical gradient

gradient caused by diffusion - gradient caused by electrophoretic movement

ohms law

V = IR

what affects rate of movement of ions

• size of electrochemical gradient

• natur eof ion - size, charge

• number of open ion channels

• properties of ion channel

low resistance creates what current

high