Membrane Transport Flashcards
what is passive transport diffusion and what are the two types
using the chemical gradient for energy , atp or energy needed
mediated and non mediated
what is mediated and non mediated passive transport diffusion ?
non mediated :transport occurs via simple diffusion
mediated : facilated difsuion using transport protein faster than simple ( non mediated diffusion) when G< 0 (favourable )
what is Z in calcaulation
charge on ion
what is fardays constant ?
96500 cmol
what 4 moleules are allowed through non mediated simple diffusion ?
small hydrophobic like
oxygen , nitrogen water , carbon dioxide
in terms of saturation kinectis what is the difference between simple and facilitaed diffusion ?
simple is slow and not saturated ( unlimited )
facilliated is fast and saturated ( can reach a max)
what is maltoporin
a bacteral protein that allow maltodexerins into the cell
what is the greasy slide
the pore is lines with hydrophobis aroamtic residues in maltose
what are aquaporins and what do they do what its sturuture
allow water in and regulate osmotic presure
its a homotetramer that has a npa motif
what are 3 key facts about ions chanels
- selective
- can be gated
- all cell have ion channels
what are 3 important things about potassium chanelles
large family of intergral membrane proteins
tetrameric
selective filter that contains the sequence that contains GYG
how do voltage potassium on channls open and close
4 arg residue move when the membrane is deplorized to open up the channles
it closes bc of a t1 domain and beta subunits
what is valinomycin?
and ionphore pecifically complesxed to potassium and transports it accross the membrane
how does gramicidin work ?
two molcules of gramcine form a transmebrane pore for hydrogen , soudium and postasssium but calcium blocks them
what is active transport systems and the two types
energy is needed transportation
1. primary transport
2. secondary transport
what is primary transport ?
transfer directly coupled with atp hydrolysis or absorption of light to push against the gradient
what is secondary transport ?
transport of a molecule down its gradient coupled with a molecule going against its gradient
what are the 3 steps for na k pump
- phosphorylate of atp at asp resiude
- conformational change the drives transport
- na get pump out k gets pumped in
what is the lactose permase
- bring out H+ nbring in lactose
