Post on 15-Jan-2016
description
Homeostasis and Transport across membranes
Ch5 p94
Types of TransportPassive Transport
DiffusionOsmosisFacilitated diffusion
Active TransportCell membrane
pumpsEndocytosisExocytosis
Movement across a membrane depends on BOTH the concentrations of particles AND their size, shape and if they dissolve in lipids!
Passive TransportDiffusion – the movement of particles from
an area of high concentration to an area of low concentrationMovement down its concentration gradientHappens naturally due to kinetic energy of
molecules Dye in a glass of water (where would it happen
faster – hot water or cold water?)
Movement of particles happens until EQUILIBRIUM is reached as long as the particles…
…can move thru the substance or across the membrane
Passive TransportOsmosis – the
movement of WATER from an area of high concentration to low concentrationHypertonic: get your
energy OUTHypotonic: Hypo the
HippoIsotonic: equal
http://www.youtube.com/watch?v=kkPiRT2ewVA&feature=related http://www.youtube.com/watch?v=iG6Dd3COug4&NR=1
Passive TransportFacilitated Diffusion – the movement of
particles is assisted by carrier proteins in the cell membrane.
Active TransportCell Membrane pumps
Sodium (Na)-potassium (K) pumps“Na Na NAAA Na, Na Na NAAA Na HEY HEY
Good bye”Our cells need the potassium in them. It
doesn’t care if there isn’t a lot outside the cell, it just wants to bring in as much as it can.
Sodium sneaks in the cell, and isn’t needed. SO…the cell uses energy to kick out the Na and bring in the K
Active Transport
Active TransportEndocytosis: endo=in cyto=cell
Pinocytosis “to drink” brings in fluidPhagocytosis “to eat” brings in large particles
or cellsThe cell membrane forms a divit and wraps
around until it connects on the other side, forming a vessicle.
Active TransportExocytosis: Exo=exit cyto=cell
When a vesicle that has formed in the cell, attaches to the cell membrane and opens up, releasing its contents out of the cell.
http://www.youtube.com/watch?v=4gLtk8Yc1Zc