transport of substances Flashcards
diffusion
-net movement of a substance from an area of higher conc to Ana area of lower conc down gradient
-random movement of ke
-does not require any energy so passive process
-until molecule evenly distributed
factors of diffusion
temp
sa;vol
conc gradient
distance
size of molecules
ficks law
rate of diffusion is proportional to sa x conc difference / distance
assuming temp stays constant
how does the bilayer formed by phospholipids effect diffusion. of substances in and out of cell
-facillitated diffusion
-allows movement of lipid soluble molecules
-preventd movement of water soluble molecules
-idea of large soluble molecules can’t pass through the proteins
diffusion directly across phospholipid bilayer
small , lipid soluble ,uncharged molecules
eg. oxygen and carbon dioxide
facilitated diffusion using channel proteins
small polar molecules and ions
eg. na+ bonds and h+
facillitated diffusion using carrier protein
larger ,lipid insoluble molecules
eg.glucose and amino aids
two ways facillitated diffusion occurs
1)protein channels
2)carrier proteins
protein channels
water filled hydrophilic channels allow water soluble ions to pass through
carrier proteins
specific molecules bind to protein changes sago and no external energy required
osmosis
osmosis the net movement of water molecules from a region of an area of high water potential to an area of low water potential through partially permeable membrane
water potential symbol
psi fork looking
Ψ
100% pure water has a unit of
Ψ 0
so all solutions have
Ψ <0
osmosis in animals in isotonic
no net movement
hypotonic in animals
water enters cell may burst
