Flashcards in  class3 Zaidi-transport Thru Membranes Deck (77)
Interactions involved in lipid bilayer:
Electrostatic and non covalent
These are frequently glycosylated on the extracellular side of the lipid bilayer
Membrane lipids and proteins
All the way transmembrane through lipid bilayer
Plasma membrane is semi
________facilitate movement of specific molecules across the Plasma membrane
Membrane transport proteins
Several hydrophobic residues for one protein the enters and leaves PM several times:
Most transport proteins are:
Polytopic transmembrane integral membrane proteins
What is advantage to polytopic membrane proteins?
Allows more diversity in binding and conformational changes
What is permeable to PM??
Lipophilic molecules via diffusion - steroid hormones
What is impermeable to the PM?
Hydrophilic/ polar substances
How can polar/hydrophilic molecules pass through PM?
Needs a specific transport mechanism
What is used for specific transport of molecules across PM?
Polytopic, transmembrane, integral membrane proteins can:
Have multiple transport domains and can shape the cell to allow more substances to pass
What determines the ionic composition of the cell?
The activity and protein levels of specific transporters
What governs the biochemical/metabolic characteristics of a cell?
Expression of specific transporters
One way of regulating metabolism
Alteration in expression levels of transporters
Ion gradient are they static?
No dynamic, but they could be thought of static in regard to they are quickly reestablished [in the way they're maintained]
Ion gradient allows for:
Membrane potential for AP
Brains uses _____ of energy
Molecules move down a [ ] gradient by using energy stored in the gradient: Ex:
Passive transport ; ion channels
Molecules move against a gradient by using biochemical energy stored in ATP: EX:
Active transport; pumps/ ATPases
Energy independent movement of molecules down a gradient:
2 types of passive transport :
Molecules that are small, nonpolar, and uncharged move freely across PM unaided
Molecules that're large and charged unable to cross the PM w/o assistance of channel or transporter
____________ of molecules is asso. W. free energy
What is used to set up an ion gradient across a semi-permeable membrane?
Ion gradients are generated by:
Membrane transporters [energy transducers]
Membrane transporters use energy from and store it as free energy of the gradient