Active membrane transport Flashcards
Active transport
movement of molecules from high to low concentration and requires energy
which ion has the lowest concentration in the extracellular space?
K
NA having high concentration outside the cell, what happens?
cell needs constant energy to complete its procedures therefore NA moves from outside to inside (high to low concentration)
K has a high concentration inside the cell, what happens?
K moves from inside to outside (along the concentration gradient)
what does active transport require
similar to facilitated diffusion, it requires carriers that combines specifically and reversibly with transported substances
what are the two types of active transport
primary active and secondary active
primary active transport uses _____ as a source of energy.
ATP, by burning glucose then used to carry body function
hydrolysis of ATP results in
Phosphorylation of the transport protein
example of primary active transport
NA/K pump - also called NA-K ATPase
channel binding to ATP before hydrolysis of phospho-regulation stimulates the channel to change its ____
shape
mechanism of NA-K ATPase:
1- The pump is in “open inside, high NA-low K affinity”. three NA ions bind and trigger the ATPase activity
2- bound ATP is hydrolyzed to ADP and P
3- Released chemical energy causes the transition of the pump molecule to the “open outside, low NA- high K affinity”
4- 2 K ions bind to the pump
5- release of dephosphorylation is triggered (p)
6- dephosphorelated pump binds to another ATP molecule, decreasing the pumps affinity to K -> relase to K into the cytoplasm
repetition of this cycle creates gradients of NA and K concentrations across the membrane
NA gradient created by primary active transport can serve as a source of energy for
secondary active transport
symport system
two substances are moved across the membrane in the same direction
antiport system
two substances are moved across the membrane in opposite directions
primary active mechanism produces
mechanisms
