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Ch11Biological Membranes and Transport - Coggle Diagram
Ch11Biological Membranes and Transport
Three major structures(lipids aggregation)are observed
Bilayers
Liposomes
Micelles
Functions of Membranes
Define the boundaries of the cell
Allow import and export(Selective)
Sense external signals and transmit information into the cell
Provide compartmentalization within the cell
Produce and transmit nerve signals
Store energy as a proton gradient
Support synthesis of ATP
Common Features of Membranes
two leaflets of lipids(bilayer). *with the exception of archaebacteria:monolayer of bifunctional lipids
asymmetric:(1)inside(2)outside(3)carbohydrates are attached in the outer leaflet(4)they can be electrically polarized
3-10nm thick
The Fluid Mosaic Model
The Composition of Membranes
Membrane composition is highly variable in different organisms
membrane composition and asmmetry
Three Types of Membrane Proteins
Amphitrophic and GPI-linked proteins
Lipid-linked membrane proteins
.
Integral membrane proteins
Transmembrane Domains
Peripheral Proteins
Membrane Phases
Liguid-ordered state(i.e. "gel phase")
Liquid-disordered state(i.e. "fluid phase")
升溫可以使膜的狀態由gel->fluid
Membrane Dynamics
Transverse Diffusion
蛋白質界導擴散
Lateral Diffusion（快）
FRAP(Fluorescence recovery after photobleaching)
:
Membrane Rafts(膜筏)：細胞膜上的“社區”(有固定成員)
舉例：Caveola和Cavolin
其他可以使細胞膜彎曲的方式
Membrane Fusion(膜融合)
舉例：神經傳導物質的釋放
Transporter on manebrane
依據要不要耗能分類
主動運輸（需要耗能）
（1）Primary active transport(against gradient)初級主動運輸
（2）Secondary active transport(against gradient)次級主動運輸
(ex)ABC Transporters
.
被動運輸（不需要耗能）
Facilitated diffusion(down gradient)
Simple diffusion(down gradient)
Ionophore-mediated ion transport(down gradient)
依據運輸物質的方向分類
Cotransport
Symport
Antiport
(ex)Bicarbonate transporter
Uniport
(ex)Glucose transporter(symporter+uniporter)
