membranes and transport
Post on 03-Jan-2016
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Membranes and Transport
Important Terms
Solvent a solution capable of dissolving other substances
Solute a minor component dissolved in solvent
The Cell Membrane
The cell membrane is in charge of what gets in to and out of the cell Import nutrients Export molecules and waste
If good stuff couldn’t get in and bad stuff couldn’t get out, the cell would die
Fluid mosaic model
The cell membrane is made up of phospholipid bilayer (‘2 layers’)
This barrier allows certain things to pass through it (eg. water, oxygen) but stops others (eg. ions, macromolecules) and is ‘semi-permeable’
=
O2
O2
H2O
H2O
Na+ Na+
extracellular
intracellular
hydrophilic
hydrophobic
Fluid mosaic model
This semi-liquid ‘sea’ of lipids has proteins floating within it that help move things across the membrane
**I will draw the important parts on the board with you...**
FYI
FYI
FYI
There are 2 types of membrane transport:1. Passive transport
Diffusion Facilitated diffusion Osmosis
2. Active transport Protein pumps Endo/Exocytosis
Transport happens through phospholipid bilayer or membrane proteins only
Back to membrane transport...
NO energy needed(it just happens!)
Energy needed(otherwise it won’t happen)
Important Terms
Permeable allowing material through
Impermeable not allowing material through
Semi-permeable allowing some material through but not others
Diffusion
Movement of molecules from an area of high concentration to an area of low concentration
Osmosis
Osmosis is the movement of water molecules through a semi-permeable membrane into a region of higher solute concentration
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